John Hefti/Associated Press

An injury to C.J. Beathard allowed San Francisco 49ers fans to finally see Jimmy Garoppolo on the field, but the players are upset about the reaction from the crowd.

"Our starting [QB] got hurt and people are cheering before he even stands up," safety Eric Reid said, per Curtis Pashelka of the Mercury News. "That pisses me off. I’m disappointed in our fans. I understand the excitement about Jimmy, he’s a great player, but that’s not right."

"First of all, I wanted to say our fans are better than that," linebacker Reuben Foster added. "You wait until a guy gets up to cheer, not when a guy's down. Then when he's up, you cheer."

Beathard started Sunday's game against the Seahawks and threw for 201 yards but left it with just over a minute remaining with a lower-body injury. Chris Biderman of the Niners Wire reported the quarterback suffered knee and hip ailments and is expected to have an MRI on Monday.

"People don’t understand what we [go] through as football players," Reid said of the fans' cheering, per Eric Branch of the San Francisco Chronicle. "And what our bodies go through. And he’s laying down on the ground and people are cheering. That’s messed up."

The injury allowed Garoppolo to make his team debut after coming over in a trade from the Patriots shortly before the deadline.

He threw just two passes, with his final attempt being a 10-yard touchdown pass to Louis Murphy:

While the 26-year-old likely represents the future in San Francisco, the fans seemed to cross a line with their excitement Sunday.