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HOUSTON -- New England Patriots receiver Wes Welker tore both his anterior cruciate ligament and medial collateral ligament in his left knee in Sunday's game against the Houston Texans, but he is scheduled to undergo more testing Monday, a source close to the situation told ESPN NFL Insider Adam Schefter.

Welker left the game in the first quarter after getting hurt on a reception and did not return. Welker tried to plant his left foot after making a catch and that's when the injury occurred.

Wes Welker is carted into the locker room after hurting his left knee.

Welker was helped to the sideline by members of the Patriots' medical staff. He buried his head in a towel while sitting on the bench and was later carted to the locker room.

Patriots coach Bill Belichick did not have an update on Welker's status after his team's 34-27 loss.

Welker caught a pass from Tom Brady on New England's first possession and his knee appeared to buckle as he turned upfield.

When Welker went down, a nearby player immediately called for medical help. Brady and receiver Randy Moss kneeled over Welker, and Belichick also walked out from the sideline to check on Welker.

Welker entered the game with 122 catches for 1,336 yards and four touchdowns this season.

Information from ESPN NFL Insider Adam Schefter, ESPNBoston.com's Mike Reiss and The Associated Press was used in this report.