Kyle Shanahan was watching from laiyongcai92's blog

as Jimmy Garoppolo scrambled toward the 49ers sideline and George Kittle Jersey , rather than safely duck out of bounds, stepped back to his right and took a wicked shot from Steven Nelson.At first, the San Francisco coach thought his quarterback had sustained a concussion.Turns out it may have been a season-ending knee injury.Garoppolo's left knee buckled just before the Chiefs' cornerback delivered a shoulder-to-shoulder blow, and that was the reason he went down so hard. Garoppolo was on the turf for a couple of minutes before he was helped to his feet and eventually carted off late in a 38-27 loss to Kansas City."We fear an ACL," Shanahan said afterward. "We'll find out more tomorrow."That's bad news for the banged-up 49ers (1-2), who already lost top running back Jerick McKinnon to a season-ending knee injury and only have two other quarterbacks on the roster.C.J. Beathard took over for Garoppolo with just over five minutes left Sunday, and he appeared to throw a touchdown pass to George Kittle before offensive pass interference wiped it out. San Francisco had to kick a field goal and that wound up being the final margin.Now, Beathard is in line to start next week when the 49ers play the Chargers in Los Angeles, and Nick Mullens could get a call-up from the practice squad to serve as the backup."Any time you lose your starting quarterback, that's a big deal. It was when we lost our starting running back, too," Shanahan said. "Feel for him personally. I know how disappointed he is."Beathard said he spoke to Garoppolo briefly in the trainer's room, and what little of their exchange he was willing to repeat made it quite clear the 49ers' franchise quarterback — who signed a five-year, $137.5 million extension in February — expects his season to be over."I told him I'll be praying for him and I love him and he just told me to lead these guys," Beathard said. "I've never been in that situation with something possibly that serious. I can only imagine how tough it is for him this early in the season."It's also a big blow for the 49ers, who thought they had the pieces to contend for a playoff spot his season. Now, they've lost two of their most important offensive pieces, to say nothing of a series of injuries on defense Sunday that left them with a piecemeal backfield.Top cornerback Richard Sherman went down with a calf injury, while backup Tarvarius Moore left with a wrist injury. Strong safety Jaquiski Tartt was inactive with a shoulder injury and free safety Adrian Colbert hurt his ankle, forcing a bunch of backups to play significant snaps.Chiefs quarterback Patrick Mahomes wound up handling them for 314 yards passing and three TDs."They do a lot of things. They use their personnel well. They have a lot of guys that are interchangeable and have a lot of tools Jimmy Garoppolo Jersey ," said backup safety Antone Exum Jr. "It's a team you have to stay disciplined on and play your assignment."Still, the 49ers leaned on running backs Alfred Morris and Matt Breida and the strong arm of their quarterback to mount a comeback. And after Garoppolo's TD toss to Marquis Goodwin in the third quarter made it 35-24, there was a sense of optimism on the San Francisco sideline.The 49ers were still trailing 38-24 when Garoppolo led them inside the Kansas City 5 in the final minutes. The Chiefs answered with sacks by Allen Bailey and Justin Houston on consecutive plays, then flushed Garoppolo from the pocket on third-and-goal from the 20-yard line.That's when the San Francisco quarterback headed for the sideline, decided to stay in play rather step out of bounds, and ultimately put the rest of the 49ers' season in question."Just like we always do, you show up to work tomorrow," Shanahan said. "We'll all be men about it. We'll grade the tape hard and see what we did wrong. And when we show up Wednesday it's time to go."It's part of the NFL season. It's what you have to do," he added. "We all feel for Jimmy. There's no doubt about it. We dealt with this with our running back, too. It's part of the NFL. We're not the first team this has happened to." SANTA CLARA, Calif. (AP) — The injury news could have been worse regarding Matt Breida, but it appears the San Francisco 49ers will be without their top running back for at least one game.Breida underwent an MRI on Monday that showed a “serious sprain” to his left ankle, according to coach Kyle Shanahan. That likely will sideline Breida for next Monday night’s game at Green Bay.“It was positive news that it wasn’t a high ankle sprain, (but) he’ll probably end up being doubtful this week,” Shanahan said.As the 49ers look to rebound from Sunday’s deflating 28-18 home loss to the Arizona Cardinals, they’ll probably have to do so without the player who’s been their best offensive weapon, so far.Breida ranks fifth in the NFL with 369 rushing yards, and his 7.5 yards per carry average leads the league among those with at least 25 rushing attempts. He enjoyed a terrific first quarter Sunday before leaving with his ankle injury.Breida has been a bright spot for the struggling 49ers (1-4), who lost projected starting running back Jerick McKinnon to a torn ACL in the preseason and then watched No. 1 quarterback Jimmy Garoppolo suffer the same season-ending injury in Week 3 against Kansas City.Without Breida, the 49ers would lean heavily on veteran Alfred Morris Mike McGlinchey Jersey , who has shared ball-carrying duties with Breida and is more of a between-the-tackles runner.Raheem Mostert is third on the depth chart, but he’s more of a special-teams contributor and he fumbled his first carry Sunday after Breida left the game.It wasn’t a surprise that the 49ers brought in several running backs for workouts Monday afternoon. One of them was Jeremy McNichols, who was among San Francisco’s training camp cuts this summer.Shanahan said the team would decide later in the week whether to sign a running back. Another option is promoting Jeff Wilson from the practice squad if Breida can’t play Monday at Green Bay.The 49ers will take a two-day break before returning to the practice field Thursday to begin preparing for their prime-time game against the Packers.Figure a point of emphasis will be protecting the ball better, after San Francisco committed five turnovers in Sunday’s loss to the previously winless Cardinals. It was the most turnovers for the 49ers since they had five against Seattle on Sept. 15, 2013.But another challenge for Shanahan is keeping his players mentally focused. Many viewed the 49ers as a potential playoff team before the season. Instead, they’ve lost four of their first five games and suffered a psychological blow when Garoppolo went down.“It’s different in this day and age where you hear everything,” Shanahan said. “It’s hard to simplify your world. And with social media, when guys go home, even if guys don’t listen to things, their wives do. Their girlfriends do. Their brothers do.“When you go through that stuff and don’t meet outside expectations, it starts to affect you. And I just try to constantly preach to our guys to be stronger than that, to try to not pay attention to that, because that’s not going to help you solve any problems.”NOTES: Receiver/punt returner Dante Pettis (left knee) already has been ruled out for a second consecutive game. Several others will be re-evaluated once the team returns to practice Thursday. They include receiver Marquise Goodwin (quad, hamstring), left tackle Joe Staley (knee), center Weston Richburg (knee), tight end George Kittle (knee) and cornerback Jimmie Ward (hamstring).