Los Angeles Chargers quarterback Tyrod Taylor is believed to have suffered a punctured lung from a painkilling injection administered Sunday by a team doctor, according to multiple people familiar with an investigation being conducted by the NFL Players Association.

The NFLPA confirmed that an investigation is underway.

“Our medical and legal team have been in touch with Tyrod and his agent since Sunday collecting facts,” George Atallah, the union’s assistant executive director of external affairs, said in a written statement posted on Twitter. “An investigation has been initiated.”

Chargers Coach Anthony Lynn acknowledged Wednesday that Taylor suffered a “complication” from the injection.

“I’m not angry at all,” Lynn said during a virtual news conference with reporters. “It happens, you know. Like I said, I can’t go into details about it. But it was a complication with the shot. No one’s perfect. I don’t think anyone on this Zoom is perfect. It happens. The doctor, I know he’s a good man. It’s just unfortunate.”

Lynn said Taylor was in the Chargers’ facility Wednesday and was “feeling fine.” Rookie Justin Herbert will start this weekend’s game at home against the Carolina Panthers, Lynn said, after making his first NFL start as a last-minute replacement for Taylor in Sunday’s loss to the Kansas City Chiefs. Lynn has said Taylor will regain the starting job when he is able to play.

A Chargers spokesman declined further comment earlier Wednesday beyond reiterating that the team and Lynn had acknowledged Monday that Taylor suffered a complication from the injection.

“I hate it for him,” Chargers tight end Hunter Henry said Wednesday in a virtual news conference. “I hate it for our team. It’s a terrible situation in every aspect of it. I’ve obviously been hurt a lot. And to have something like that happen, I can’t imagine what both sides are going through. It’s such a tough situation, man, and I hate it. It [stinks]. It’s not ideal. It’s not great.”

Henry said he trusts the team’s medical staff.

“I still have faith in our medical staff,” Henry said. “Obviously this is an unfortunate event. It’s not good. I know none of us think it’s good at all. But we’re going to continue to move forward, and I do have faith in them.”

Chargers defensive tackle Linval Joseph expressed similar sentiments, adding that he was particularly upset because Taylor was involved.

“It’s hard to really talk about that,” Joseph said. “But I’ll just say this: Mistakes happen. It could have been Tyrod. It could have been a regular person. It could have been another athlete. It [stinks] to hear when things like this happen. But it [does] happen all the time. I’m upset it had to be Tyrod. Let’s just say it like that.”

The NFL did not respond to a request for comment.

Taylor was expected to start Sunday for the Chargers against the Chiefs in Inglewood, Calif., but was scratched from the lineup shortly before kickoff because of what at the time was called a chest injury. Herbert, the sixth overall selection in the NFL draft in April, was told just before kickoff that he would start the game. Herbert played well as the Chargers lost in overtime to the Chiefs, the defending Super Bowl champions, at SoFi Stadium.

Taylor reportedly received the painkilling injection for a rib injury. According to ESPN, which first reported that Taylor’s lung was punctured by the injection, Taylor suffered two cracked ribs in the Chargers’ season-opening victory over the Cincinnati Bengals. A team doctor administered the injection and Taylor ended up being hospitalized Sunday night for the injury and breathing issues, according to the ESPN report, which said that doctors have advised Taylor not to play indefinitely.

“I really wasn’t angry because I know the man, and he’s a very good man,” Lynn said. “He’s a very good doctor. But like I said, there was complications with the shot. But I know the man. And so I know it wasn’t intentional. Everyone makes mistakes. I can’t explain it. It’s just what happened.”