Texans running back Arian Foster left Saturday night's preseason game against the 49ers with a hamstring injury. Foster has been dealing with a hamstring injury for a majority of training camp and he's unlikely to play in Houston's preseason finale next week. He posted a message on his Twitter account Sunday morning, thanking fans for their concern and criticizing the negativity coming from fantasy football owners. "4 those sincerely concerned, I'm doing ok & plan 2 B back by opening day. 4 those worried abt your fantasy team, u ppl are sick," he wrote.