After halting practice for a second time because of a brawl on Tuesday, coach Kyle Shanahan called for his team to huddle up.

He promptly delivered some choice words about what had just transpired. Underneath the anger was a simple message about how Shanahan wants his team to play.

Physical? Absolutely. Tough? Of course. Irritating? Sure.

But Shanahan wants the Niners to draw the line at throwing punches, which happened twice in that Tuesday practice -- namely between star middle linebacker Fred Warner and receiver Brandon Aiyuk.

"I want everyone challenging each other," Shanahan said on Friday.