Walter had a left shoulder injury and Ward injured his right ankle.
The team said on Sunday night that both injuries were still being evaluated, but NFL Network insider Jason La Canfora cited a league source in reporting that Walter will miss 10 to 12 weeks with a broken shoulder.
Ward started for Arian Foster, who was inactive with a left hamstring injury. Ward scored on a 1-yard run in the first quarter.
Walter had one catch for 14 yards before he left the game. He said he would have an MRI exam on Monday.
"I wouldn't say I'm worried about it, because I'm going to treat the heck out of it and be ready to roll as soon as possible," Walter said after the game. "I've never had anything like this before, so it's always a concern."
Walter has played in all but two games for the Texans since he signed as a free agent before the 2006 season. He started all 16 games in 2010, catching 51 passes for 621 yards and five touchdowns.
The Associated Press contributed to this report.