Kyle Shanahan blamed the state of the MetLife Stadium field after the San Francisco 49ers lost star pair Jimmy Garoppolo and Nick Bosa to injuries.
49ers head coach Shanahan said Bosa "most likely" suffered an anterior cruciate ligament (ACL) injury in Sunday's 31-13 NFL win over the New York Jets, while quarterback Garoppolo sustained a high-ankle sprain.
Defensive end Bosa was carted off the field in the first quarter for last season's Super Bowl participants and Shanahan told reporters: "Some key players with some bad injuries, which makes it always a little bit harder.
"I thought it was a real good game by the team. But you've got a little bit of mixed emotions when you lose some guys like that.
"I don't know why it happened. As far as the feeling that was on the sidelines, I know that's as many knee injuries and ankle stuff and people getting caught on the turf as I have ever been a part of.
"From what I saw, the other team did, too. I know our players talked about it the entire game, just how sticky the turf was ... It was something our guys were concerned about right away and the results definitely made that a lot stronger. Unfortunately this is a place we've got to go back to next week."
49ers defensive linesman Arik Armstead, whose team host the New York Giants in Week 3, added: "[It brings] a lot of anxiety. We see guys you love go down and get hurt and we've got to come back here and play again on the same surface, and that's anxiety-provoking, to see that happen and know you have to do it again."
On Garoppolo, who finished the half and went for 14-of-16 for 131 yards and two touchdowns before sitting out the game, Shanahan said: "We'll see how that heals.
"You've got to get on a plane tonight, he'll wake up tomorrow [Monday], it will probably feel much worse, but that's something you really won't be able to tell whether he has a chance or not probably until the end of the week."