That's bad news for a team that has lost two straight heading into a key AFC South game on Sunday against the division-leading Tennessee Titans.
Schaub said being banged up is just part of life in the NFL and that the team will have to work through its problems to get ready for the Titans. Schaub was limited in practice on Wednesday, with backup Matt Leinart taking some of the repetitions. The Texans plan to use Leinart a lot in practice as the season goes on to give Schaub some rest.
"He's just sore," coach Gary Kubiak said of Schaub. "He's beat up, but he did practice ... Matt is pushing through and we just need to get him through a week where he's not getting beat up very much."
Kubiak said Johnson has been making progress and hasn't had any setbacks. He has been running and catching passes, but has yet to practice with the team. Kubiak said he could return to practice before the end of the week and wouldn't rule him out for Sunday yet.
"Well, first off, I'm not going to say no. I'm not going to say it," he said when asked if there was a chance Johnson would play. "He's got to reach the practice field before he plays in a game and he's not done that yet. Everything is going exactly the way we thought it would go."
With Johnson's status uncertain, the Texans are looking for more from recent acquisition Derrick Mason, who joined the team last Thursday in a trade with the New York Jets and caught three passes for 27 yards in a 29-14 loss to Baltimore on Sunday.
Schaub thinks Mason can play a bigger role in the offense against the Titans with a full week of practice under his belt.
"He can really help us with his skill set," Schaub said. "So to get him more preparation and get more reps with him will help us going forward."
Mason said he's spent a lot of time in the film room and that he's trying to get caught up as quickly as possible.
"I'm picking up on things fairly quickly," Mason said. "The rest of the guys are helping me as much as they can. I feel like this week I can play a little bit faster because some more things have been thrown my way and I feel comfortable with them."
Kubiak said playing without Johnson and Casey has been difficult, but that players such as Mason and fullback Lawrence Vickers have to pick up the slack.
"All of a sudden, you lose Andre and then you lose (Casey) and his versatility," Kubiak said. "It's been tough, but Lawrence has got to step in and he's got his strengths too as a player. Derrick has to step in offensively. It's been an adjustment period, but it's something we have to handle as a group and find a way to make it work."
Kevin Walter, who normally starts opposite Johnson, has 11 receptions for 133 yards and a touchdown in the two games combined since Johnson has been out. He knows that he can do more, but said that filling the void can't fall to just one guy.
"We're missing some big guys -- Andre, Mario -- and we've got to get past that," he said. "Obviously it does hurt us, but we need to step in and make those plays. Not just one person but everyone needs to go in there. We've got to pick it up as a whole group."
The Texans placed S Dominique Barber on injured reserve with a foot injury and signed rookie S Shiloh Keo from the practice squad to take his roster spot. ... The Cleveland Browns signed RB Chris Ogbonnaya to their active roster from Houston's practice squad and the Texans signed RB Javarris Williams and S Torri Williams to their practice squad.