"It was pain(ful)," Foster said. "I was a little scared, but at the same time, trust me, if you can't put no pressure on it, then you should be worried, but when you put enough pressure on it, then you have got some hope. That's all I was just hoping for. It was painful, but at the same time, I knew nothing was seriously damaged."
As it turned out, Foster was correct. What looked to be a potentially devastating injury to one of the team's best young players turned out better than it first appeared. Although Foster still has some tests to do and the Niners aren't offering an exact return window, Foster said after the game that he will be back "very, very, very soon."
On a second down draw play by Carolina with 3:33 left in the opening quarter, Foster moved toward Carolina running back Christian McCaffrey, but his right foot appeared to catch on the playing surface as he lunged forward. Foster immediately grabbed for his lower right leg as medical personnel rushed to him.
Foster's teammates huddled around him, with many saying prayers, and Niners fans began chanting his name as he was taken off the field. The injury was initially announced as a leg ailment, with Foster labeled questionable to return.
In the locker room, Foster had X-rays performed on his ankle and leg. Those tests revealed that nothing was broken, and the diagnosis was changed to an ankle injury.
"It was more optimistic than it looked," coach Kyle Shanahan said. "We've still got to do more tests and stuff. He couldn't return. It was some type of ankle injury. It was definitely better than it seemed out there.
"They thought at first it was possibly a tibia [fracture], and they came out and told me at halftime that it was negative, but he wasn't good enough to go back in the game."
Foster returned to the field in full uniform early in the second quarter and did some tests with the team's trainers on the sideline. Although Foster admitted to lobbying to return to the game, he said the determination was made to not rush him back for fear of making it worse.
After halftime, Foster returned to the sideline and remained in uniform, though he removed his shoulder pads.
"I just wanted to go back out there and support and show everybody that I'm not down, you shouldn't be down, I'm good, I'm all right," Foster said. "A lot of guys were worried."
Before the injury, Foster had been making a strong first impression. He had three tackles, one for loss and a pass defended on the first two-plus defensive series. Ray-Ray Armstrong replaced Foster with the starting defense, finishing with six tackles.
When Foster departed, the 49ers and Panthers were tied at 0, but the game quickly slipped away after he left. On the next play, the Panthers scored on a 40-yard pass from quarterback Cam Newton to receiver Russell Shepard. Carolina went on to reel off the game's first 20 points before the Niners scored.
"Reuben is a guy that we definitely want out there," Shanahan said. "I thought it was a little deflating when you have a big turnover like we did, especially when on the play, it was a chance to have an explosive touchdown. So that was deflating on offense and then to have a turnover instead of that and then to lose a guy on the next play and then I think they went down two plays later."