Career sacks leader Mario Williams missed most of the season with a torn chest muscle, Matt Schaub sat out the final six weeks with a broken right foot and star receiver Andre Johnson's numbers were down as he fought through hamstring injuries.
The Texans still earned the franchise's first division title and playoff victory on the strength of the league's second-ranked defense, another stellar season by Arian Foster and the emergence of third-string quarterback T.J. Yates.
"The key is that you stay focused on your goals and you stay focused on the work," Kubiak said, "because you never know how something is going to happen."
Houston lost to Baltimore in the divisional playoffs, and most believe the Texans have the pieces in place to go at least that far in 2012.
Team owner Bob McNair headed off one potential distraction in June, extending the contracts of Kubiak and general manager Rick Smith, which were both due to expire after this season.
The Texans lost Williams in free agency and traded linebacker DeMeco Ryans, but every other key cog in Wade Phillips' 3-4 defense returns, including leading tackler Brian Cushing and Pro Bowlers Johnathan Joseph and Antonio Smith. Houston allowed only 285.7 yards per game, despite learning Phillips' new scheme on the fly because of the lockout.
"We can play a little more sound," said Cushing. "I think if anything, what we didn't know last year we made up with effort. That's something we hope to continue this year and play hard and just impress people when they turn on the film. And that's something we want to continue to do."
Cushing also had four sacks and two interceptions, outside linebacker Connor Barwin led Houston with 11 1/2 sacks and 27 quarterback hits and rookie defensive end J.J. Watt led the team with 13 tackles for loss.
"Football is just a whole lot more fun playing for him," Cushing said of Phillips. "You're free, you play loose, and you just go out there and have a good time."
Houston's biggest free-agent pickup was veteran Bradie James, who played for Phillips during his stint as the Cowboys' defensive coordinator and head coach.
"He's real familiar with what we're doing and how we want it done and what changes we need to make in the heat of the battle," Phillips said. "That's what I like about him."
Watt and outside linebacker Brooks Reed adapted to starting roles, and the Texans used their first-round pick on Illinois sack specialist Whitney Mercilus, who'll add depth at outside linebacker.
All the questions for the Texans coming into this season seem to be on offense.
Johnson, who turned 31 on July 11, missed organized team activities following arthroscopic surgery on his left knee. The five-time Pro Bowler played in only seven games last season because of injuries to both hamstrings. The Texans drafted DeVier Posey and Keshawn Martin and waived disappointing Jacoby Jones.
"They're both rookies and we've thrown a lot at those two guys," receivers coach Larry Kirksey said during OTAs. "It's just a learning process for them, and I think they're both going to be fine."
Schaub threw for more than 4,000 yards in 2009 and `10, but then he fractured the Lisfranc joint in his right foot, raising the same old questions about his durability. Yates proved a capable fill-in, winning his first two starts and playing well in Houston's playoff victory against Cincinnati.
Foster carried the offense, though, topping 1,200 yards rushing despite missing three games with a hamstring injury. The one-time undrafted rookie signed a five-year, $43.5 million contract in March, after making the Pro Bowl for the second straight season.
The Texans set franchise records for yards rushing (2,448) and ranked second in the league in rushing in 2011 (153 yards per game). Houston cut right tackle Eric Winston and lost right guard Mike Brisiel in free agency, disrupting the continuity on one of the NFL's sturdiest offensive lines.
Rashad Butler and Antoine Caldwell are penciled in to replace Winston and Brisiel. Kubiak also raves about 2011 draft pick Derek Newton and the Texans drafted Brandon Brooks, a 350-pound multi-position lineman out of Miami, (Ohio).
Houston also drafted Texas A&M kicker Randy Bullock, the 2011 Lou Groza Award winner. He'll compete with veteran Shayne Graham, who signed with the team in May.