San Francisco 49ers receiver Brandon Aiyuk and linebacker Fred Warner got into it on Tuesday, as the pair exchanged punches twice over the objections of head coach Kyle Shanahan.

The biggest fight between the two happened after Warner sent receiver Marcus Johnson to concussion protocol with a late hit.

While players said the day’s hot temperature and a long, full-pads practice contributed to the tetchiness, according to ESPN, Shanahan made clear that Friday’s incidents were over his limit.

‘I want everyone challenging each other,’ Shanahan said Friday, according to the site. ‘I don’t care how much c**p each other talks; I don’t care how close they get to fighting.

‘They can do whatever they want to get themselves to be as intense as they want and bring the best out of each other, which happens a lot that way. And it’s the same on the field.

‘But once you throw a punch, you get ejected or you get a penalty, and we pride ourselves on, I want people to be irritants, I want people to get as close as they can to all that stuff. I want people to get right on the line where they’re about to black out, but you can’t black out on the football field or you cost your team.’

Aiyuk and Warner’s beef did not come as a complete surprise, as Aiyuk (maybe somewhat jokingly) called his teammate ‘annoying’ and ‘irritating’ days earlier.

Warner, by his own telling, sees his own ribbing of Aiyuk as a way of improving him.

‘Specifically with Brandon, I chose him out,’ Warner said. ‘I think he’s ready to make that next step into playing at an elite level. I’ve gotten after him a little bit… because I know how much he has in him.

‘And I know if I nag him a little bit, he’s going to get sick and tired of that and start to hold his own. He’s started to really gain that mindset of knowing he’s a guy and he’s capable. I’m trying to get the best out of him. That’s it.’

Aiyuk was a 2020 first-round pick (25th overall) who has shown promise but has yet to fully break out.

After posting 748 receiving yards in his rookie year across 12 games, he appeared in all 17 contests last year but only ticked up to 826.

Things appeared to calm down for San Francisco after things got violent between Aiyuk and Warner.

There were no incidents on Wednesday, according to ESPN, and a video posted to Twitter that day showed the pair seemingly smoothing things over after practice.