Yahoo Sports reports: MLB Commissioner Rob Manfred said in a letter to Missouri Republican Sen. Josh Hawley that the San Francisco Giants failed to properly explain to players that they were allowed to decline to wear rainbow-themed caps during the club's annual Pride Night earlier this month. Several members of the Giants, including starting pitcher Landen Roupp, added Bible verses to the themed cap, prompting a warning from the league that writing on the caps is a violation of league policy.