Following Major League Baseball’s warning to three San Francisco Giants players who inscribed Bible verses on their caps during the club’s Pride Night celebration, Sen. Josh Hawley (R-Mo.) penned a letter to commissioner Rob Manfred citing concerns over what he called a “pattern of discrimination” against Christian players.

“MLB has said this is a content-neutral policy and that MLB ‘respect(s) players’ right to free expression,’” Hawley wrote. “But this is dubious, given that MLB is openly promoting a political viewpoint and possibly compelling adherence to that viewpoint.”

MLB declined to comment on Hawley’s letter, though it issued a statement earlier on Tuesday.

“To be clear, this routine verbal warning not to wear the hat in future games is not disciplinary and had absolutely nothing to do with the content of the message,” the league said in a statement to The Athletic. “We respect players’ right to free expression. … We have given the same warning numerous times in the past to players for messages such as ‘Dad,’ ‘Happy Mother’s Day, I Love Mom’ and names of family members.”

The Giants players were not fined or subject to any disciplinary action by the league.

Hawley’s open letter to Manfred stemmed from Friday’s series opener against the Chicago Cubs, when three Giants pitchers — Landen Roupp, J.T. Brubaker and Ryan Walker — inscribed some variation of “Gen 9: 12-16” on their Pride Night caps. A fourth, Sam Hentges, declined to wear the hat altogether, opting for San Francisco’s standard black hat with orange lettering.

MLB Pride Night hats have included on-field apparel in which the club’s logo on the hat is filled with a rainbow, a longstanding symbol for the LGBTQ+ community.  The Bible verse the pitchers wrote on their caps refers to the rainbow as a covenant between God and “every living creature.”

“It’s just about God’s covenant and a promise that he makes to us that, you know, his faithfulness and his mercy,” Roupp told reporters. “That’s just kind of something I believe in, and I stand firm in that, and I’m thankful we live in a country where, you know, we have the freedom to believe what we want … and express what we want.”

In response to fallout from the players’ decisions, the Giants released a statement apologizing for the pain it might have caused to the community.

“The San Francisco Giants are proud to support Pride Night and the LGBTQ+ community. Baseball should be a place where everyone feels welcome, respected, and valued.

“We also respect that individuals may make personal choices about participating in team activations. We understand that the choices by individual players have caused pain and anger to many in the LGBTQ+ community and we are sorry for that.  Those choices do not change our organization’s commitment to inclusion, belonging, and creating a welcoming environment for all.

“We remain grateful to our fans, partners, employees, players, and coaches who help make Pride Night a meaningful celebration.”

MLB’s uniform regulations stipulate that a “Player may not write, attach, affix, embroider or otherwise display nicknames or messages on apparel or playing equipment.”

MLB players have, at times, broken those rules, however.

In the last World Series, Los Angeles Dodgers and Toronto Blue Jays relievers wrote Alex Vesia’s No. 51 on their hats in a show of solidarity for the reliever, who missed the championship after the death of his newborn daughter. Earlier last season, following the assassination of conservative activist Charlie Kirk, Blake Treinen, a Dodgers reliever, drew two crosses with Kirk’s name in the middle of it on his hat. It hasn’t been publicly revealed whether those messages resulted in a warning from the league.

The three Giants players who wrote on their caps weren’t the first to make a statement regarding Pride Night, which has been adopted by every big-league team except the Texas Rangers.

Earlier this season, two Dodgers players, Treinen and Alex Call, did not wear the team’s rainbow Pride Night hats. Last season, Dodgers pitcher Clayton Kershaw inscribed the same Bible verse from Genesis on his hat during the club’s Pride Night. It isn’t known if Kershaw was warned by the league.

In 2022, five Tampa Bay Rays players — Jason Adam, Jalen Beeks, Brooks Raley, Jeffrey Springs and Ryan Thompson — opted out of wearing the club’s rainbow-colored hat and peeled off a rainbow patch on the right sleeve of their team-issued jerseys. At the time, Adam called it a “faith-based decision.”

In his letter, Hawley pointed to the Washington Nationals’ decision to fire a community relations executive after he was taped in a hidden camera conversation revealing internal deliberations about what he said was a social media ban on a Catholic pitcher. Hawley said the incident showed MLB’s “anti-Christian bigotry.”

The executive, Sean Hudson, said that pitcher Trevor Williams was not used in certain social media content following his condemnation of the Los Angeles Dodgers for hosting the Sisterhood of Perpetual Indulgence, a satirical volunteer group, at their stadium in 2023.

In citing MLB’s antitrust exemptions, Hawley has asked Manfred to respond to a list of five requests by June 19, including guidance on marking apparel and equipment, as well as policy on player participation on Pride Nights, among other demands.

“The freedom to live out one’s faith does not end at the ballpark gate,” Hawley wrote.