HOUSTON --
Texans defensive end
J.J. Watt suffered a tibial plateau fracture in his left leg on Sunday on the
Kansas City Chiefs' first drive of the game and is out indefinitely.
Watt will undergo further testing on the leg. His recovery timetable is uncertain, sources told ESPN's Adam Schefter.
Watt fell to the ground while engaged in a block on the play. The Texans later announced the diagnosis.
Dallas Cowboys middle linebacker
Anthony Hitchens suffered a tibial plateau fracture in August and was given a recovery timetable of eight weeks. Dallas receiver
Dez Bryant suffered a tibial plateau fracture last season and missed three games.
Watt was seen exiting the X-ray room on crutches before he left the stadium in an ambulance.
Watt was helped to the sideline by the Texans' training staff, and he was looked at in the sideline tent before being taken off on a cart.
Watt's younger brother
T.J. Watt, a linebacker for the
Pittsburgh Steelers, tweeted his support.
The three-time NFL Defensive Player of the Year missed the last 13 games of the 2016 regular season because of a back injury. He played in his first regular-season game since his September 2016 back surgery in this season's opener against the
Jacksonville Jaguars. In four games, Watt had 13 tackles, but he did not have a sack.
Texans outside linebacker
Whitney Mercilus injured his chest on the same drive and was ruled out for the rest of the game.