De’Vondre Campbell didn’t want to play football Thursday night, so he told 49ers coach Kyle Shanahan how he felt and then left Levi’s Stadium.

Shanahan was asked in his postgame media session why Campbell went to the locker room in the third quarter of the 49ers’ 12-6 loss to the Rams.

“Yeah, he said he didn’t want to play today,” Shanahan said.

Shanahan told reporters that he asked Campbell if he wanted to come into the game in the third quarter to sign returning starter Dre Greenlaw, and Campbell declined without giving a reason.

Campbell wasn’t in the locker room after the game when reporters were let in to talk to the players.

Shanahan said he didn’t know immediately whether the team would release Campbell, a 31-year-old former All-Pro who signed with the 49ers in March after being released by Green Bay.

Cornerback Charvarius Ward said Campbell shouldn’t have dressed for the game if he wasn’t ready to play.

“He definitely hurt the team because Dee (Winters) was out and we needed a linebacker,” Ward said. “I think (Demetrius Flannigan-Fowles) was broken too, so for him to do that is pretty stupid for me. He’ll probably be circumcised soon, so that’s what it is.”

Tight end and captain George Kittle expressed confidence in his teammates’ enthusiasm to play despite Campbell’s decision.

“I think anyone in this building who is asked to go in, I think 100% of anyone would die to get on that football field,” tight end and captain George Kittle said. “People go through random things off the field. I can’t say anything about that. … It’s hard to win football games if someone doesn’t want to play football, especially if you’re fit. It kind of makes you depressed, especially when you’re down two linebackers.”

Team captains Fred Warner and Nick Bosa declined to comment on Campbell’s resignation when asked after the game.