49ers' star tight end George Kittle sidelined with a potentially severe hamstring injury in Week 1.

San Francisco 49ers tight end George Kittle was sidelined in the second quarter due to a hamstring injury during their Week 1 game against the Seattle Seahawks. Kittle scored the 49ers' only touchdown in the first half, but his absence is a significant loss for the team, which is already dealing with other injuries. The team's early ruling on Kittle suggests the injury could be severe.