The 49ers are expecting Staley to miss six to eight weeks with the injury. But, after the 41-17 win Sunday, they were optimistic enough that it could be on the lower end of that time frame that they don't believe Staley will land on injured reserve. The early expectation is that the injury will not require surgery.
"From what I hear so far, we'll find out more tomorrow but it should be less than eight weeks, so I don't think he'll be an IR candidate," coach Kyle Shanahan said. "But we'll find out more tomorrow. I think it's something he's had before."
Staley did suffer a similar injury in Week 10 of the 2010 season and did not return that season, though that team was out of the playoff mix and likely would have required postseason contention for him to make it back.
After Sunday's game, Staley left the locker room wearing a walking boot on his left leg and using crutches. Before departing, he vowed to be back and to help as much as possible while recovering.
"I'm going to do everything I can to be part of this team for an end-of-season run," said Staley, who is in his 13th NFL season. "I have a lot of years and knowledge. I've always thought that after my football career ends as a player, I'd give coaching a try. Now maybe I'll have some time to try it. I'm bummed."
Staley suffered the injury with 2:21 left in the third quarter as he was downfield blocking for running back Raheem Mostert. Replays showed that another player was thrown down and then leg-whipped Staley in the shin.
After a couple of minutes, Staley was able to limp to the sideline, where he waited for a cart to take him to the Niners' locker room. He did not return to the game after rookie Justin Skule replaced him.
Right tackle Mike McGlinchey said his understanding was that Staley suffered a "hairline" fracture and is looking forward to getting his bookend tackle back sooner than later.
"It's unfortunate that we lost him," McGlinchey said. "He's obviously a huge, key part of our team and our offensive line. But next man up. Justin Skule has been preparing for the past couple of weeks and we're confident in his ability to get the job done. We're going to play hard for Joe for these next couple weeks while he's out."
While McGlinchey would seem a candidate to flip to the left side in Staley's stead, Shanahan indicated that move wasn't part of the initial plan to replace Staley. Shanahan said he didn't believe the positions to be much different and is hesitant to disrupt two spots on the line because of one injury.
The 49ers also lost backup swing tackle Shon Coleman to a dislocated right ankle in the preseason, an injury that landed him on injured reserve.
That means Staley's job likely will fall to Skule, whom the 49ers picked in the sixth round of this year's NFL draft. Daniel Brunskill, who can play all over the line, is likely to be the backup tackle, though the Niners could look for more depth. Sam Young, whom the Niners signed after Coleman's injury, is unsigned.
"Anytime you lose your left tackle it's always significant, especially when the guy who backed him up we lost in preseason," Shanahan said. "We have got Skule, we've got Brunskill, guys who will have to step it up. It's unfortunate for Joe. I know how bad he wants to be out there ... at least we'll still get him back this year."