In a passing league, the adage about a roster never being well-stocked enough at cornerback keeps ringing true.

And the Texans built their defense with that recurring thought in mind. Especially as they prepare for a demanding schedule that includes veteran quarterbacks like the Green Bay Packers' Aaron Rodgers

The top three cornerbacks are Johnathan Joseph, Kareem Jackson and Kevin Johnson All are former first-round draft picks, with only Joseph arriving as a free agent.

With sizable fourth cornerback A.J. Bouye emerging as a valuable reserve with his upgrades of confidence and skill this offseason, the Texans now have enviable depth at the position. The Texans also have special-teams contributor Charles James as a fifth cornerback.

"We have a pretty deep corner position," Texans coach Bill O'Brien said. "When you look at our top four, five, six corners, these guys are all good football players. Some have different types of skill sets, they can do different things. Some guys can play safety.

"Some guys can help us a whole ton on special teams. It's a good group of guys. For the roster question, it's another tough decision; how many to keep. It's a very competitive group."

Roster downto 75 players

The Texans negotiated an injury settlement with veteran defensive end Jeoffrey Pagan, removing him from the roster as they got down to the NFL limit of 75 players.

Pagan is a former sixth-round draft pick from Alabama who played in 22 games for the Texans over his first two NFL seasons, recording just 11 tackles and no sacks. He was hurt throughout training camp.

Meanwhile, the Texans waived-injured outside linebacker Gerald Rivers and cornerback Duke Thomas (hamstring).

The Texans officially placed rookie center Nick Martin (ankle surgery), safety Kurtis Drummond (leg) and kicker Ka'imi Fairbairn (quadriceps) on injured reserve.

Reserve safety Lonnie Ballentine was placed on the reserve-physically unable to perform list as he continues to recover from torn knee ligaments suffered last season. Under NFL rules, Ballentine must miss at least the first six games.

The Texans also released defensive tackle Ra'Zahn Howard, wide receiver Tevin Jones (League City), inside linebacker Ryan Langford, wide receiver Josh Lenz, offensive tackles Matt Pierson and Arturo Uzdavinis, and outside linebacker Carlos Thompson

The Texans still have some difficult decisions to make as they'll cut the roster to 53 players by Saturday. It's particularly tough at running back, where Lamar Miller is the starter, Alfred Blue is the backup and rookie Tyler Ervin is the primary kickoff returner.

Osweiler showshis knowledge

The knowledge that quarterback Brock Osweiler has displayed of the Texans' intricate playbook has been hard-earned.

Osweiler began a crash course in the system of coach Bill O'Brien and offensive coordinator George Godsey immediately after signing his four-year, $72 million contract in March.

Haunting darkened film rooms and asking teammates plenty of questions, Osweiler has gained a comfort level and recall of the nuances of a complicated offense.

Osweiler is done for the preseason since he won't play in the Texans' game Thursday night against the Dallas Cowboys following an impressive performance against the Arizona Cardinals in which he completed 11 of 13 passes for 146 yards and one touchdown with no interceptions for a 139.1 passer rating. In three preseason games, Osweiler completed 27 of 39 passes for 297 yards, two touchdowns and one interception for a 97.9 passer rating.

"One of the things we've seen that has been very impressive and has to continue during the season is his command of the offense," O'Brien said. "When we watch the tape, one of the things that stands out to me, personally, is his knowledge and his command of the offense.

"That has to continue to improve. We can't take a step back with that. That's what I would like to really see him continue to do when the season starts."

Backup QB'improved'

The development of Texans backup quarterback Tom Savage has been highlighted by more decisiveness, faster reactions and a deeper understanding of the offense.

After spending last season on injured reserve when he sprained his shoulder in the preseason finale against the Dallas Cowboys, Savage will start against them again Thursday night at AT&T Stadium before giving way to third quarterback Brandon Weeden

Through three preseason games, Savage has been sharp in relief of starter Brock Osweiler He's completed 25 of 47 passes for 318 yards, three touchdowns and no interceptions for a 95.9 passer rating. His completion percentage has been the least impressive part of his game, a 53.2 percentage.

"I think he's improved," Texans coach Bill O'Brien said. "I'd just like to see steady improvement from him. One of the things that we have to do at that position Thursday is take care of the football, manage the game properly, move the sticks on third down, execute in the red area, get us into the right plays.

"I think communication with the huddle, if we go no-huddle, all those different things. I just want to see steady improvement from him, and then Brandon will play, too, and see steady improvement from him."

McNair on team:'very competitive'

Following an offseason when the Texans dramatically overhauled their offensive, Texans owner Bob McNair expressed optimism about the defending AFC South champions' outlook.

The centerpiece of the changes was signing quarterback Brock Osweiler to a four-year, $72 million contract. The Texans upgraded their speed by signing former Miami Dolphins running back Lamar Miller and drafting wide receivers Will Fuller and Braxton Miller

The Texans have won all three of their preseason games.

"We'll be a very competitive team," McNair said during the Texans' kickoff charity luncheon Tuesday. "We'll be very exciting."

Aaron Wilson