The Texans (8-3) knocked down Jacksonville 20-13 on Sunday, Nov. 27 to record their first-ever five game winning streak.
According to the Associated Press, Leinart may have broken his collarbone.
"There's a pretty strong possibility I probably won't be coming back this season," Leinart, who finished with 57 yards passing and touchdown pass to Joel Dreessen, said.
Third-string quarterback T.J. Yates made his NFL debut and connected with Pro Bowl wide receiver Andre Johnson, who caught his first pass after sitting out for six games with an injury. Yates finished the contest with 70 passing yards and a passer rating of 66.0
Arian Foster racked up 65 yards and a touchdown by leaping over a pile for his 27th career TD.
The Texans defense sacked Jacksonville quarterback Blaine Gabbert six times, four of which were recorded by Connor Barwin.
Atlanta travels to Reliant Stadium on Sunday, Dec. 4 in what will be a huge test for the Texans.
Houston's four wins in the division match the most in franchise history.