Houston coach Gary Kubiak says "all the tests came back good" and they expect him to be OK in time for the team's opener Sept. 9 against Miami.
Kubiak didn't rule out Watt playing in the preseason, but isn't sure exactly how long he'll be out.
"Adversity makes you stronger," Watt said on Twitter. "I will be on the field against the Dolphins. Better than ever."
According to the Houston Chronicle, Watt was injured when he got his arm caught in a tangle of players at the end of a running play.
Selected 11th overall in the 2011 NFL draft, Watt registered 5½ sacks during his rookie campaign.
Information from ESPN NFL Insider Adam Schefter and the Associated Press was used in this report.