HOUSTON -- The Houston Texans have handled adversity well.
They may be challenged now to win without star receiver Andre Johnson.
Coach Gary Kubiak said Monday that Johnson is nursing an injured right hamstring and his availability for Sunday's game against Oakland is uncertain as the team seeks other medical opinions.
Kubiak said that Johnson will "miss some time," though he said that could range from 3-4 days to a "few weeks."
"We're still in the evaluation process," Kubiak said. "We are dealing with a hamstring, we do know that. We are going to get a couple of different opinions here, over the course of the next two days."
Kubiak said it's not unusual for the team to seek extra medical input on players' injuries.
"A lot of our guys will get second opinions, just trying to decide what's best," Kubiak said.
"Obviously, with Andre, there's big concern. At the same time, we've got to do what's best for Andre. That's what we've got to do right here, so that he understands exactly what's going on, so we understand exactly what's going on."
Johnson went down without getting touched in the second quarter against Pittsburgh on Sunday, and did not return.
The Texans (3-1) still found a way to beat the Steelers -- a mark of progress for a franchise known for collapsing when things start to unravel.
Not this time. Arian Foster rushed for 155 yards, including the game-clinching touchdown, and the defense held onto the lead as Johnson watched from the sideline.
"You don't replace Andre," Kubiak said. "What you do is you've got to pick it up across the board, at other spots."
Before Johnson went down, Houston already proved it could play well without Foster, the NFL's leading rusher last season.
Foster was hampered by a hamstring injury during training camp and into the season, and 2010 second-round draft pick Ben Tate topped 100 yards rushing in Houston's first two games, both victories.
Kubiak is hoping Jacoby Jones can fill in for Johnson as ably as Tate did for Foster.
The 6-foot-2, 210-pound Jones caught 51 passes for 562 yards in 2010, his fourth season with Houston, and he signed a three-year deal in the offseason. He has seven catches for 91 yards this season.
"Jacoby's grown up a lot as a player," Kubiak said. "He's much better in the run game than he has been in the past. He's very capable of making big plays."
Foster may also have to carry the heavy load against the Raiders (2-2).
Tate left Sunday's game with a groin injury, and Derrick Ward, Foster's original backup, has been out since spraining his right ankle in the opener against Indianapolis.
Kubiak said both players are "day to day" for Sunday's game.
Foster already seems as if he's regained his 2010 form, looking strong in 30 carries against the Steelers.
"We've always leaned on him pretty good," Kubiak said. "When we run the football 30-35 times in a game, we're usually playing pretty good football as a team. I like to think we can do that every week."
Casey caught five passes for 126 yards, including a diving touchdown, in Houston's 40-33 loss to New Orleans. Daniels made two catches to set up Foster's winning run on Sunday, and Walter had a touchdown catch against the Saints.
And more than ever, Kubiak has confidence in Houston's defense.
The Texans rank fifth in sacks (12) and fourth in scoring defense (17.5 points per game). Ben Roethlisberger was sacked three times and Houston's defense allowed only 43 yards on Pittsburgh's last four series in the final 12 minutes.
"Knowing that we could pin them and the way we were playing defense all day, that's a great feeling as a coach," Kubiak said.
Also, unlike past seasons, the Texans have figured out how to deal with their own mistakes. Two Houston touchdowns were nullified by penalties on Sunday, and the Texans were flagged nine times overall.
"Way too many of them," Kubiak said. "But the thing I was most proud of is we did have so many that could've hurt us, could've sent us in a negative direction I guess is a way to put it. We didn't do that. We kept overcoming them as a football team. You could sit there and feel sorry for yourself, but we came right back and made the next couple plays to win the game."