What is the Rosin Bag Used for in Baseball?

what is the rosin bag for in baseball

Last updated on November 3rd, 2023 at 08:38 am

A rosin bag is a small canvas bag that can be kept on the field by the pitcher’s mound during a game. The pack contains rosin powder, which is a sticky substance baseball pitchers can apply to their bare hands while pitching to get a better grip on the ball.


Rosin powder comes from the sap of fir trees (a type of pine tree). It is a white, chalk-like, sticky powder, also known as powdered pine tar. Its stickiness helps keep the pitcher’s hands dry by drying off sweat. It also helps them get a better grip on the baseball.


Rosin bags are typical in other sports where athletes need to improve their grips, such as rock climbing, gymnastics, weightlifting, bowling, tennis, and more.


Questionable Rosin Bag Use in 2023

Questionable Rosin Bag Use in 2023

The New York Yankees pitcher, Domingo German, on 4-15-2023 was stopped by the umpires as he was walking off the mound against the Twins. The check by umpires is standard, and most of the time results in nothing. However, the umpires did stop Domingo for a bit of time and did feel his hands because something felt different. Domingo did come out the following inning to pitch and stated that it was from a misunderstanding using the rosin bag.


A few games later, Max Scherzer of the New York Mets, got ejected from a game against the LA Dodgers. Max claimed that he was only using a rosin bag, but the umpires felt differently. The league handed Max Scherzer a ten-game suspension since they believe that the substance was something foreign. 


General Rules of the Bag on the Baseball Field

general rules of the bag on the baseball field

Before 2020, rules would allow one shared rosin bag that would stay on the back of the pitcher’s mound or in the on-deck circle and be shared by all the pitchers. After the coronavirus pandemic, the rules are different so that each pitcher has their own individual rosin bag that they bring on and off the field with them when they go up to the pitcher’s mound. Pitchers can only pick up and use the rosin bag after time is called, and the pitcher steps off the rubber.


What’s the Difference Between Rosin and Pine Tar?

What's the Difference Between Rosin and Pine Tar

While rosin powder originates from dried pine tar, it is different from straight plain pine tar. Non-powdered pine tar can be used on hitters’ bats to give them a better grip on the bat when they swing. You can only apply pine tar to the first 18 inches of the bat, so it only makes contact with the hitter’s hands and not the ball.


Pine tar and other sticky substances such as Vaseline, maple syrup, dirt, wax, sandpaper, and more are forbidden for pitchers to use on their hands or the baseball. The main reason other substances are banned is the spin rate those substances help create for pitchers.


Is Rosin Legal in baseball?

Rosin is legal in major and minor league baseball for pitchers to use. It is the only foreign substance that is legal for pitchers to apply to their hands to get a better grip on the ball. The primary purpose of rosin is to dry a pitcher’s hands to throw better via a better grip.


For example, a pitcher sweating won’t have control over their pitch to a hitter. Without that secure grip, a pitcher might accidentally hit the hitter due to their lack of feel for their pitch. Just like other sports using rosin for a better grip, baseball wants their pitchers to be in control when throwing a ball during a game.


However, like anything in baseball, some players use a rosin bag to better grip by mixing it with other substances. Obtaining a better grip can make your pitches more precise, but finding ways to improve the spin rate can make your pitch more challenging to hit. Mixing the rosin bag with illegal substances, like Spiker Tak, can dramatically increase your spin rate on your pitches. The extra spin rate means a more dramatic drop in a breaking ball, for example.



How is a Rosin Bag not Illegal Like Other Substances?

A rosin bag helps dry up your hands, which leads to a better grip on a ball. However, a sticky substance like Spider Tack makes gripping the ball easy, which can dramatically amplify your pitch’s spin rate since your fingers leave the ball later. While a rosin bag can help you get a better grip to throw a pitch more effectively, other substances give that unnatural sticky layer to your fingers, which dramatically increases the spin rate of pitches.


Are rosin bags sticky?

Rosin is a dry powder that becomes sticky when combined with the sweat and moisture of your hand. So, rosin powder becomes sticky when pitchers rub it onto their hands and mix it with their sweat. This stickiness or tackiness significantly improves their grip on the ball.


However, rosin itself is not particularly sticky because it is dried and powdered. The canvas used in rosin bags also helps keep the rosin powder from retaining too much moisture inside the bag. Therefore, rosin bags themselves should not be very sticky.



In summary, rosin bags and other substances create a tricky situation for MLB and what to do next. While the original purpose of the rosin bag was to create a better grip for pitchers, some players started doctoring their arm and hat with other substances to create an even better grip with the rosin bag. The rule changes in 2021 were interesting because of the number of no-hitters taking place, so MLB went ahead and made a rule change in the middle of the season, which they usually don’t.


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