The Major League Baseball season may have just gotten underway last week… But that hasn’t stopped New York Yankees stars Alex Rodriguez and Mariano Rivera from showing their support for the documentary Bully.

Rodriguez and Rivera joined fellow players Derek Jeter and Curtis Granderson, as well as the team’s manager Joe Girardi, for a special public service announcement to urge the audience to sign on to a website for the film and its Bully Project petition.

Directed by filmmaker Lee Hirsch, Bully follows several middle school students from around the country during one school year and documents bullying and the middle school environment. In one scene, shot in Sioux City, Iowa, middle school student Alex Libby is taunted by classmates on the school bus; another shows an LGBT teen in Oklahoma who faces bullying over her decision to come out. The film also follows the family of Georgia teen Tyler Long in the year following his suicide after he was bullied in middle school.

The film provoked controversy when the MPAA originally gave the movie an R rating, citing the language used in the film. That decision was later overturned after a national letter-writing campaign.

Rodriguez, Rivera and their Yankees teammates join a growing list of celebrities who have spoken out against bullying, including Victoria Justice and Wilmer Valderrama.

Bully opens in theaters around the country on Friday.