Houston, TX (SportsNetwork.com) - Houston Texans quarterback Ryan Mallett will miss the remainder of the season.

Texans coach Bill O'Brien on Monday said the team was still evaluating the quarterback, who reportedly suffered a torn pectoral muscle, but on Wednesday the fourth-year pro was placed on season-ending injured reserve.

Mallett was on last week's injury report with a strained chest muscle, listed as questionable for Sunday's game against Cincinnati. He tried to play through the injury against the Bengals and struggled during the contest, completing only 21-of-45 passes for 189 yards with an interception in the 22-13 loss.

The Houston Chronicle on Monday reported the severity of Mallett's injury and said he would need season-ending surgery.

Mallett was making just his second career NFL start last Sunday. He had taken over for Ryan Fitzpatrick in Week 11 against Cleveland and threw for 211 yards with a pair of touchdowns and an interception in a 23-7 win.

The 26-year-old is in his first season with the Texans, who acquired the Arkansas product from the New England Patriots in a trade just prior to the start of the campaign.

Fitzpatrick started the first nine games and is expected to return to the role. He has connected on 61.8 percent of his passes for 1,960 yards with 11 touchdowns and eight interceptions this season.

The Texans on Wednesday also signed quarterback Thad Lewis, who started five games for the Buffalo Bills last season.

Lewis appeared in six games overall in 2013, throwing for 1,092 yards with four touchdowns and three interceptions.

Houston also signed safety Terrance Parks to the practice squad.