Houston ? The Houston Texans’ decision to snub Heisman Trophy winner Reggie Bush and sign defensive end Mario Williams with the No. 1 pick in the NFL Draft has cut a slack-jawed swath across the NFL.

But general manager Charley Casserly said the move Friday night shouldn’t be that surprising.

“I think if people had just listened to what we had said, they would have seen that we were serious about Mario Williams,” Casserly said. “Once we brought him in here our statements never changed that we were seriously considering him for the first pick in the draft and I understand that people didn’t believe it, but we always said it and we believed it.”

Houston started negotiating with both Williams and Bush this week. While many expected the Southern California running back to be the Texans’ choice, they went for the North Carolina State lineman instead.

“This is a decision that took a lot of time to make, but at the end of the day we felt this was the best player for our football team,” Casserly said. “Both players, Reggie Bush and Mario Williams, are going to, I think, be great pros. We made the decision to go with defense.”

The Texans signed Williams to a six-year, $54 million contract, with $26.5 million guaranteed. San Francisco quarterback Alex Smith, the top pick in last year’s draft, got a six-year, $49.5 million contract from the 49ers, with $24 million guaranteed.

Though most believed Williams was simply a bargaining tool to aid negotiations with Bush, Casserly said the team was “serious” about Williams long before they brought him in for an April 10 visit.

“It’s just we were never going to tell anybody that,” Casserly said. “We weren’t going to deny it, but nobody asked the question and I understand why they wouldn’t ask the question early on.”

Bush has been embroiled in some controversy this week concerning who paid the rent for a home his parents lived in, and whether an agent was involved – which would be an NCAA rules violation. But Casserly said that did not influence their decision.

“Absolutely not,” he said. “We believe in Reggie Bush as a person. We asked him and his attorney the different allegations and both of the denied them. Both of them said that Reggie didn’t do anything wrong so we obviously took him at his word.”

The Texans’ move left the New Orleans Saints with an opportunity to take Bush as the No. 2 pick. Saints spokesman Greg Bensel said Friday night the team had no comment.

Williams is the first defensive end taken No. 1 overall since Courtney Brown went to the Cleveland Browns in 2000. He also is the 12th defensive lineman to be picked at the top of the draft.

The 6-foot-6 1/2, 292-pound Williams, who left school a year early to enter the draft, has been described as a cross between Julius Peppers and Lawrence Taylor.

He saw his stock soar after his amazing performance at the NFL combine in February, running the 40-yard dash in 4.73 seconds, and doing 35 repetitions on the 225-pound bench press.

There were some questions about his work ethic after getting sacks in 11 of his last 23 games, but he has the potential to dominate.

“I have the size and the speed and the athleticism, and to find that in a defensive end is rare,” Williams said earlier this week at an interview session in New York. “You just don’t see it all the time. I think the last time was Julius Peppers and you know what kind of player he is.

“Everywhere I went, they said, ‘We want you.”‘

Houston is moving to a 4-3 defense in its first year under new coach Gary Kubiak after scrapping Dom Capers’ beloved 3-4 scheme after he was fired, creating the need for true defensive ends.

Williams surely will help a Texans defense that ranked 31st total defense last season; 32nd against the rush and 24th against the pass. The Texans have lacked a legitimate pass rusher the last two seasons with the declining health and productivity of two-time Pro-Bowl defensive end Gary Walker whom Houston recently released.

Williams will join former Baltimore defensive end Anthony Weaver who was signed last month. Weaver had 117 tackles and 14.5 sacks in four years with the Ravens.

“Our pass rush hasn’t been what it needs to be,” Casserly said. “Mario Williams can give you a pass rush from the defensive end position and the defensive tackle position. He can play all four defensive line positions. He’s fast, he’s quick, and he’s athletic. The guy, in our opinion, is a natural pass rusher and can play the run.”

A gamebreaking running back like Bush seemed like an obvious choice to many, who saw the Texans offense sputter and routinely fail to score touchdowns en route to last season’s 2-14 record.

The 6-foot, 200-pound Bush had 1,740 yards rushing and 2,890 all-purpose yards this past season for the Trojans as a junior. He decided to leave school early to enter the draft after USC lost to Texas in the national championship game.

The move also signifies the team remains confident in the abilities of running back Domanick Davis, who signed a five-year contract reportedly worth more than $21 million before last season.

“The bottom line is he’s going to be here and he’s going to play, so you’ve got a player already there that’s proven,” Casserly said.