San Francisco Giants starting pitcher Landen Roupp was among players warned for including an inscription of a Bible verse on his Pride Night hat during a loss Friday to the Chicago Cubs. File Photo by Tannen Maury/UPI | License Photo

June 16 (UPI) -- MLB issued warnings to several San Francisco Giants players who wrote Bible verses on Pride Night hats, pointing to rule violations.

Giants pitchers Landen Roupp, J.T. Brubaker and Ryan Walker each sported Biblical references on their hats during a 5-1 loss the Chicago Cubs on Friday in San Francisco.

The collective bargaining agreement (CBA) between MLB and the MLBPA states that players who violate uniform regulations will first receive warnings, specifying that they will be subject to further discipline if they do not "immediately cease violating" the regulations.

"The writing on the cap violates our rules, and consistent with normal practice, we have warned the players about future violations," MLB said in a statement.