The San Francisco 49ers kept Christian McCaffrey on the field in their 17-13 win over the Seattle Seahawks, but another star offensive weapon is expected to miss multiple weeks after leaving the game early.Tight end George Kittle, who scored the teams first touchdown of the year on Sunday in Seattle, left the NFC West bout with a hamstring injury. That injury is expected to keep him out three to five weeks, according to NFL Network.Head coach Kyle Shanahan made the announcement on Monday after the win, saying that Kittle would miss a "few weeks." Shanahan added that no decision has been made about placing Kittle on injured reserve.CLICK HERE FOR MORE SPORTS COVERAGE ON FOXNEWS.COMWhile Kittle isnt going to be playing this upcoming week, there is a chance that starting quarterback Brock Purdy may not play, either.Shanahan said that Purdy is dealing with left shoulder and toe injuries, and he wouldnt guarantee his quarterback would be able to play against the New Orleans Saints. Shanahan also said the toe was the worse of the two ailments.START STREAMING WITH A 7-DAY FREE TRIAL AT FOXONE.COM OR DOWNLOAD THE FOX ONE APP ON YOUR FAVORITE DEVICE"Not sure, has to see how it heals and how the week goes on it," Shanahan said of Purdy.If Purdy isnt available for the 49ers, his backup is veteran Mac Jones, the New England Patriots 2021 first-round pick who didnt pan out. He moved on to the Jacksonville Jaguars, where he gained experience stepping in when needed.Jones appeared in 10 games, seven of which were starts, in place of Trevor Lawrence last season for the Jaguars. Jones threw for eight touchdowns and eight interceptions during his time as the Jaguars quarterback.Finally, wide receiver Jauan Jennings suffered a shoulder injury that also knocked him out of the game early. But the 49ers avoided a serious situation, as ESPN reported Jennings MRI came back clean. However, they will be looking at it again with a CT scan.Unfortunately for the 49ers, they have dealt with serious injuries to key players in recent seasons, most notably McCaffrey and his bilateral Achilles tendinitis last season.But McCaffrey looked spry as usual to begin his ninth NFL season, tallying 69 rushing yards on 22 carries while catching nine passes from Purdy for 73 yards.The 49ers will be forced to have other players on the depth chart step up, including Jake Tonges, the backup tight end who scored the game-winning touchdown late in the fourth quarter.Follow Fox News Digitalssports coverage on X, and subscribe tothe Fox News Sports Huddle newsletter.