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Complete Guide to RIF and SEV Index Baseballs

  • Originally conceived by Worth, Inc. (now owned by Rawlings), the Reduced Injury Factor (RIF) traces back to its pioneering work in polycore softball innovation for baseballs and softballs. The term Severity Index (SEV Index) emerged roughly at the time, invented by MacGregor sporting enterprise, referencing a similar construction approach for baseballs and softballs.
  • RIF / SEV Index baseballs are softer and more compressible than traditional baseballs, reducing the risk of injuries for young players
  • Using RIF / SEV baseballs allow for safer learning environment for children to develop their baseball skills while minimizing the fear of injury


During the warm summer months, people of all ages engage in America’s favorite pastime by lining the streets and parks with baseballs, bats, and gloves.

Baseball is an exciting sport, especially for young children who are just beginning to learn the intricate rules and proper techniques, but parents must keep in mind of the injury risks.

In 2021, roughly 15.6 million Americans above the age of five-year-old played baseball. [a1]

Nearly 110,000 children from ages 5 to 14 were treated in hospital emergency rooms for injuries, such as concussions, broken bones, dislocations, and blunt chest trauma, from getting hit by a high velocity baseball. Worse yet, approximately three to four children dye from baseball injuries each year. [a2]

Diamondback’s Chris Iannetta getting hit in face

Statistically, a chance of getting severely injured is very low but that is of little comfort if your child falls into that bucket,

We will review and learn how Reduced Injury Factor (RIF) baseballs (sometimes referred to as Reduced Impact Factor) may be used in youth baseball to minimize some of these injury risks.

Please note that some manufacturers use the term Severity Index (SEV) , originally coined by MacGregor, to describe similar baseballs.

History of Reduced Injury Factor (RIF) Baseballs

Baseball is one of the safest sports, but on rare occasion, injuries occur when a thrown or batted baseball traveling at high velocity hits a player.

Let’s review some baseball history to understand why using RIF or SEV baseballs in youth baseball is a good idea .

During the Dead-ball era in baseball (1900-1919), they made the inside of a baseball from melted rubber soles. This rubber core was too soft, preventing batters from hitting the ball far.


In addition, each game used a single baseball causing further performance degradation.

Both National League and American League (they were two separate entities before merging to form the Major League Baseball) introduced a cork-centered ball invented by Ben Shibe [b1] to address the complaints from fans (and some players) about the low-scoring games. New cork-centered baseballs dramatically improved the batting averages.

The unfortunate side effect of livelier baseballs was the number of injuries. Injury concerns peaked when Ray Chapman, a Major League player, died in August 1920 [b2] after being struck in the head by a pitch.


This tragedy led to increased scrutiny of baseball, with many calling for changes to make the sport safer.

During the 1980s, advances in technology and manufacturing processes resulted in the development of the Reduced Injury Factor (RIF) baseball by Worth Inc. sporting goods company. (SEV Index is the term used by MacGregor).


Many baseball purists will say that RIF and SEV baseballs are sacrilegious since millions of kids and adults play baseball, and the number of injuries is small. [b3] However, it is worthwhile to consider using the RIF or SEV Index baseball in youth baseball leagues to prevent major injuries.

What is an RIF / SEV Index Baseballs?

The term RIF(1) was originally created by Worth, Inc., a sporting goods company originally founded by George Sharp Lannom Jr. in Tullahoma in 1912 as Lannom Manufacturing Company (Worth, Inc. is now part of the Rawlings Sporting Goods brand owned by MLB). Leveraging its experience developing polycore softball technology, Worth developed Reduced Injury Factor (RIF) baseballs and softballs.

SEV Index was coined by MacGregor sporting company roughly at the same time to describe similarly constructed baseballs and softballs.

RIF / SEV baseballs are designed to decrease the risk of injury while preserving the integrity of the sport.

There are three main levels of RIF/SEV baseballs:

  • RIF 1 / SEV Index Level 1
  • RIF 5 / SEV Index Level 5
  • RIF 10 / SEV Index Level 10

(1) Please note that some websites state that “RIF” stands for “Reduced Impact Force.” The correct term is Reduced Injury Factor, as per Rawlings.

RIF1 / SEV INDEX Level 1 Baseballs

Level 1 baseballs offer the highest level of safety (beyond a basic tee-ball) of all RIF balls.

MacGregor SEV Level 1 baseball comes with genuine leather, wide baseball stitches and raised seams. The inner core consists of a dense, rubber ball wrapped with a thin thread (used to bond to the leather covers).

MacGregor SEV Index Level 1 / RIF 1
MacGregor SEV RIF Level 1 – Core

Although the leather cover is an improvement over the tee-ball’s synthetic cover, it is heavily bleached and thin.

These balls are intended for kids who just graduated playing tee-ball and can be used for games or for practice for 6-7 year old players.

RIF5 / SEV INDEX Level 5 Baseballs

RIF 5 baseball has medium-level of compression and are slightly firmer than RIF1 balls.

Older MacGregor SEV Index Level 5 baseball core came with Tri-Flex Safety Core (green) which is more spongy and soft compared to new ball core (bluish gray) that is more hard and dense.

MacGregor SEV IDEX Level 5 baseball – old
MacGregor SEV IDEX Level 5 baseball – new

Level 5 baseballs are commonly used among eight to nine-year old players (ex. intermediate youth leagues)

According to Wilson, a Level 5 ball is 85% softer than a regular baseball.

RIF10 / SEV INDEX Level 10 Baseballs

With the lowest level of compression among RIF baseballs, SEV INDEX Level 10 baseballs behaves closest to traditional baseballs in terms of firmness.

MacGregor SEV IDEX Level 10 baseball

They are often used among children between nine to ten year old players.

Level 1 / Level 5 / Level 10 Cores

All cores have the same dimensions ( 8/7/8″ circumference) and weight (4.3 ounces).

On a very non-scientific test (dropping the core balls from 3 feet onto a concrete floor with laminate flooring), the results are:

  • RIF 1 / SEV Index Level 1 – 6″ initial bounce height, 5 bounces, dull sound
  • RIF 5 / SEV Index Level 5 – 6″ initial bounce height, 5 bounces, sharper sound
  • RIF 10 / SEV Index Level 10 – 5″ initial bounce height, 4 bounces, dull sound

RIF / SEV vs Regular baseballs

To the naked eye, RIF and SEV baseballs are identical to the traditional hard ball**.  They both have 9 to 9.5 inches in circumference, weighs roughly 5 ounces, and have the same number of stitching.


** when comparing a leather covered traditional ball to a leather covered RIF / SEV baseball.

The big difference is what is inside the ball.  A regular hardball contains wound yarn and/or fiber with a cork pill. In contrast, the core of a RIF/SEV baseball consists of polyurethane foam that is soft and compressible.


Some proponents of the RIF/SEV baseballs say it performs equal to a hardball, but based on my own experience, that is not the case as batters will experience a reduction in power when hitting an RIF baseball.

State Regulations and Acceptance Challenges

The youth baseball leagues, such as Little League and Babe Ruth League, recommend using RIF or SEV Index baseballs for younger age groups or divisions with inexperienced players (ex. Recreation leagues) because these baseballs are designed to be softer and less dense, reducing the risk of injury from being hit by the ball.

Many states in the United States adopted regulations to follow the guidelines set forth by national youth baseball organizations such as Little League Baseball and Babe Ruth League, effectively resulting in the use of RIF / SEV Index baseballs in many youth leagues across the country.

Note on State Resolutions
State legislatures in New York, Georgia, Texas, Michigan and Tennessee passed resolutions urging children’s baseball organizations to adopt stronger safety measures.

In addition, five cities-Ann Arbor (MI), Toledo (OH), Rockville (MD), Tallahassee (FL), and Roanoke (VA) have mandated the use of youth safety baseballs and softballs in affiliated league play.

Please note that state resolutions are recommendations only so your state’s affiliated league may follow different rules.

Today, RIF / SEV Index baseballs have gained significant traction in youth leagues, where the emphasis is placed on safety rather than performance.

Despite the benefits associated with RIF / SEV Index baseballs, the adoption has been slower or even absent in more advanced leagues as players and coaches express concerns that performance differences between RIF / SEV Index and traditional baseballs may hinder the proper development of players’ abilities and skills.

Additionally, many raised concerns that polyurethane-based RIF / SEV baseballs will negatively impact the environment where traditional balls are bio-degradable. To ensure your child’s safety, you should consult your parks and recreation department or local baseball leagues to see what kinds of baseballs are used for young players.

League Adoptions

Most major youth baseball leagues, such as Little League, Babe Ruth (Cal Ripken), PONY, and American Legion recommend using RIF / SEV Index baseballs for youth players under 13 years old and traditional baseballs for 13- or older players playing on a big field (please refer to the Complete Guide to Baseball Field Layout for more information on field sizes)

Your local league may use specific brand of RIF / SEV Index baseballs so make sure to check your representative.

Please don’t forget to visit Buying Baseballs – Reference Articles page to read other fascinating information about baseballs!

Suggested RIF / SEV Index Baseballs

Please remember that Worth, Inc. is now part of Rawligs Sporting Goods (owned by MLB).

You can also look at different types of baseballs here.

RIF 1 / SEV Index Level 1

RIF 5 / SEV Index – Level 5 Baseballs

RIF 10 / SEV Index – Level 10 Baseballs


The emergence and development of Reduced Injury Factor (RIF) or SEV (Severity) Index baseballs have profoundly influenced the game of baseball, especially within youth leagues where safety remains paramount.

As the emphasis on safety persists within the youth baseball community, the demand for RIF / SEV baseballs is expected to rise, prompting manufacturers to continuously refine RIF / SEV baseball’s performance and safety features.

Experimentation with innovative materials and technologies aims to produce even safer balls that still deliver the preferred feel and performance of a traditional baseball.

In addition to safety baseballs, you will want to read about Heart Protection for Youth Baseball Players

What is a SEV INDEX baseball?

This terminology was created by MacGregor so this rating convention is mostly used in MacGregor baseballs.

For example, MacGregor SEV INDEX Level 5 baseballs (Model MCB5SV05) may be indicated by other brands the following way:

However, please do note that SEV INDEX Levels are sometimes used interchangeably with Reduced Injury Factor (RIF) rating. For example, you may see MacGregor SEV INDEX Level 1 – Model MCB5SV01 referred to as MacGregor RIF-5 baseballs.

There are three distinct levels of SEV INDEX Levels assigned to three age brackets.

SEV INDEX Level 1 Baseballs

  • The softest baseball out of three baseballs, SEV INDEX Level 1 baseballs are recommended for Ages 5 through 7 (but primarily used by 6 year old players just after Tee ball division)
  • Unlike Tee balls like MacGregor #56 Official Tee Balls or Rawlings Youth Tball Model TVB, SEV INDEX Level 1 baseballs are firmer but still provides plenty of deflections to reduce the sting when hit
  • SEV INDEX Level 1 baseballs like MacGregor MCB5SV01 come with genuine leather cover which provides better grip (especially for small hands)
  • SEV INDEX Level 1 baseballs also tend to come with raised seams for better throwing control

SEV INDEX Level 5 Baseballs

  • The middle model out of three SEV INDEX baseballs, it is designed for Ages 8 through 12 but in most leagues, these baseballs are used by 7 year old players (Farm AA in Cal Ripken or Minors in Little League
  • These baseballs are noticeably firmer than SEV INDEX Level 1 baseballs so getting hit will definitely sting
  • A good example a baseball in this category would be MacGregor Model MCB5SV05

SEV INDEX Level 10

Frequently Asked Questions

Is tee ball same as RIF1 or SEV Index Level 1 baseball?

  • Yes, in almost all cases, RIF1 / SEV Index Level 1 baseball is identical to baseballs branded as “tee ball”

What are safety baseballs?

Safety baseballs, often referred to as “reduced injury factor” or “soft-strike” baseballs, are designed to minimize injury risk for younger, less experienced players. They have a softer exterior and interior to lessen the impact force if a player is struck.

Why are safety baseballs recommended for young players?

Young players are still developing their hand-eye coordination and reaction time, making them more likely to be hit by the ball. Safety baseballs reduce the chance of serious injuries, promoting a safer environment to learn and play baseball.

What is the difference between RIF 1, RIF 5, and RIF 10 baseballs?

RIF 1, RIF 5, and RIF 10 are hypothetical designations (as of my last update in 2021). Typically, numbers associated with RIF could denote different levels of “softness” or “reduced injury factor”. Lower numbers could suggest a baseball closer to a regular baseball in hardness, while higher numbers might be softer and thus safer.

What ages are safety baseballs recommended for?

While this can depend on the specific league and player skill level, safety baseballs are generally recommended for players aged 12 and under.

How do safety baseballs impact the gameplay?

Safety baseballs can be slightly less predictable in their movement and may not travel as far as standard baseballs. However, they provide a great way for beginners to learn baseball fundamentals without the fear of injury.

Do safety baseballs fit on a standard tee and in regular gloves?

Yes, safety baseballs are typically designed to be the same size as standard baseballs, so they should fit on a standard tee and in regular baseball gloves.

Are safety baseballs more expensive than regular baseballs?

The prices can vary, but safety baseballs are generally comparable in price to standard baseballs. Their cost can depend on factors like brand, quality, and where they’re purchased.

Do professional leagues use safety baseballs?

Professional baseball leagues do not use safety baseballs. They are mainly used in youth leagues, training sessions, and for beginner players who are still learning the game.

Can safety baseballs be used for pitching practice?

Yes, safety baseballs can be used for pitching practice as long as the cover is made from leather (to prevent gumming up the wheels).