Delhomme worked out with the Texans on Tuesday, along with another retired quarterback, Jeff Garcia. The 36-year-old Delhomme will back up rookie T.J. Yates, a fifth-round pick slated to start Sunday's game against Atlanta.
Rick Smith, Delhomme's agent, said in a phone interview Tuesday that his client has been staying in shape and raising racehorses in Louisiana since he was cut by Cleveland in July.
"He relishes that role, and he's looking forward to contributing to the team," Smith said in a phone interview. "He keeps himself in shape, he's been throwing a bunch."
Houston signed Kellen Clemens last week after learning that Schaub will need season-ending surgery on his right foot. Leinart broke his left collarbone in Sunday's 20-13 win over Jacksonville.
Yates replaced Leinart late in the first half, and went 8 for 15 for 70 yards in his first NFL action. Coach Gary Kubiak confirmed Monday that Leinart was out for the year and said Yates would start against the Falcons.
Smith didn't know if Delhomme would be No. 2 or No. 3 on the depth chart this week. But Smith said Delhomme would only consider playing for a handful of teams if he ever came back, and Houston was one of them.
"Gary runs a very quarterback-friendly system," said Smith, who also represents former Texans quarterback Sage Rosenfels. "It's a great offensive system, and quarterbacks, they love it."
Delhomme guided Carolina to the Super Bowl after the 2003 season -- played at Reliant Stadium. He completed 16 of 33 passes for 323 yards and three touchdowns in the Panthers' 32-29 loss to Tom Brady and New England.
Houston plays the Panthers at Reliant on Dec. 18.
Cleveland signed Delhomme to a two-year contract in March 2010, but he sprained his right ankle in the opener, lost his starting job to rookie Colt McCoy and played in only five games. He threw only two touchdown passes with seven interceptions that season.
But the Texans could hardly afford to be picky.
With Yates thrust into a starting role, Houston will have to lean on its top-ranked defense and No. 3 rushing attack to navigate through the final five games and earn the franchise's first playoff berth.
Despite losing a key player seemingly every week, the Texans are having their best season. They've won five in a row and hold a two-game lead over Tennessee in the AFC South.
"They've got a lot of people telling them they can't do something," Kubiak said of his team Monday. "Believe me, they believe they can. It's been about the team all year long and it will continue to be that way. It's just another obstacle. We'll rally and get ready to go this week."
The Texans rank second in pass defense (175.8 yards per game) and fourth against the run (92.5 yards per game). They have 35 sacks, second in the league to Baltimore, and they're plus-11 in turnover ratio.