Plenty. Gary Kubiak is out in favor of new coach Bill O'Brien, hired to kick-start Houston's offense. That begins at quarterback, where Matt Schaub is widely viewed as a goner. Defensive coordinator Wade Phillips has been replaced by Romeo Crennel, who's promised to expand on his beloved 3-4 scheme for a multiple defensive front that keeps J.J. Watt involved as an active, quarterback-crushing centerpiece -- perhaps alongside the athletically freaky Jadeveon Clowney.
» RB Ben Tate: Consider him history. Tate is on record saying that he "won't return" and plans to test the market. He was a logical fit for the Cleveland Browns when Michael Lombardi was in place as general manager, but his landing spot is now a mystery. ESPN New York's Rich Cimini hears the New York Jets might pursue the tough-nosed, 25-year-old runner.
» DE Antonio Smith: Smith was expected to go, but the defensive end recently told KILT-AM that his agent said O'Brien and the Texans are high on the defender. "Good player," O'Brien told ESPN.com's Tania Ganguli at the combine. "Have a lot of respect for Antonio and what he's done in this league." Smith's 32, so don't expect a long-term deal if he sticks around.
» OL Wade Smith: Also on the wrong side of 30, Smith's coming off a subpar season that saw him finish as the league's 53rd-ranked guard, per Pro Football Focus. He was a Pro Bowl-level lineman in 2012, but don't be surprised to see Houston move on. Young Ben Jones looms as a possible replacement.
Other key free agents: RB Ray Graham, RB Jonathan Grimes, RB Deji Karim, RB Chad Spann, FB Greg Jones, TE Garrett Graham, OL Andrew Gardner, OL Ryan Harris, DT Earl Mitchell, LB Joe Mays, LB Darryl Sharpton, CB Elbert Mack
What they need
Any team in the league could use Clowney's scary gifts, but if the Texans pass him up, they're going quarterback. O'Brien told me at the combine that he isn't ready to make a decision on Matt Schaub's fate, but we'd be stunned if Houston doesn't release him (a move that saves $4 million against the cap). Young (and inexpensive) Case Keenum has a better shot to stick around, but the Texans are bound to draft a young signal-caller. Also on offense, a replacement for right tackle Derek Newton makes sense. Depth at running back is another target area if Tate vanishes and Arian Foster continues to battle durability issues.
On defense, Crennel's scheme calls for outside linebackers who can heat-seek opposing passers, and Brooks Reed isn't the answer. Houston also could use help at cornerback after Brice McCain struggled through a brutal campaign.
On the way out?
» QB Matt Schaub: We're beating a dead horse here. Schaub's release feels as secure as the rising sun.
» TE Owen Daniels: Cutting Daniels saves the Texans $4.5 million. The 31-year-old tight end acknowledged last month that he might not be back on the heels of an injury-marred campaign. With backup Garrett Graham set to become a free agent, Houston might wind up starting over at the position in 2014.
Offseason crystal ball
Gregg Rosenthal got into an elevator at the combine with a pack of Texans and Colts assistants. When the Texans contingent exited, Rosey heard one Colts staffers say, "Man, I hope they don't (expletive) draft Clowney."
I expect them to do exactly that. I also anticipate O'Brien adding one, even two, rookie passers to the roster.
From there, the Texans -- about $6.2 million under the cap -- can free up space by cutting Schaub and Daniels to start. That money should be used to add depth at linebacker, offensive line and in the secondary. People have whispered about Foster as a possible cut, but that would trigger just $1 million in savings and $7.5 million in dead money. Won't happen.
If O'Brien has learned anything from his time as an assistant to New England Patriots coach Bill Belichick, look for Houston to generate plenty of roster churning from top to bottom as the new coach gets "his guys" in place.