Petrino was hired to succeed Houston Nutt, who stepped down at Arkansas two weeks ago and became the head coach at Mississippi.

Petrino was introduced as the 30th Razorbacks coach by incoming athletic director Jeff Long at a late-night news conference Tuesday.

"It is a tremendous honor for me to be named the 30th head coach at Arkansas, particularly on a night when we honored coach (Frank) Broyles for his 50 years service," Petrino said, referring to former head coach and outgoing athletic director Frank Broyles. "He's such a legend and I can't wait to develop a relationship with him."

In January, Petrino left as head coach at Louisville to take over in Atlanta, agreeing to a five-year, $24 million contract handed out by a team that felt he could help Michael Vick reach his full potential.

However, the star quarterback came under investigation for a grisly dogfighting operation that led him to plead guilty to federal charges. On Monday Vick was sentenced Monday to 23 months in prison without ever taking a snap for Petrino.

On Monday night, the Falcons lost to New Orleans 34-14, and hours later Petrino left the team with a 3-10 record to return to the college ranks.

"Today was a day of decision," Petrino said. "It was difficult on one side, very easy on the other. It was difficult to leave Atlanta, the staff, players, fans. The timing of it probably the think that made it most difficult."

Arkansas had been looking for a coach for two weeks to replace Nutt, who resigned after a tumultuous season of his own. The Razorbacks came close to hiring Wake Forest's Jim Grobe last week, but Grobe remained with the Demon Deacons and Arkansas fans had to wonder whether the school could attract a big-name coach.

In Petrino, the Razorbacks found one. Petrino went 41-9 in four years at Louisville, coaching some of the highest-scoring teams in the country before leaving in January to join the Falcons.

Petrino received a standing ovation from the Arkansas supporters who came to his introductory news conference.

"Coach, this is just the tip of the iceberg," chancellor John White announced.

Petrino left Louisville for Atlanta in January, agreeing to a five-year, $24 million contract handed out by a team that felt he could help Vick reach his full potential.

"I believe this is truly the best football job in the NFL," Petrino said at his introductory news conference. "It was an easy decision for me."

Of course, he had no idea what Vick was doing in his spare time.

A few months later, the star quarterback came under investigation for a grisly dogfighting operation that led him to plead guilty to federal charges. He was sentenced Monday to 23 months in prison without ever taking a snap for Petrino, who left with a 3-10 record.

The Falcons declined further response beyond a terse, two-paragraph statement released Tuesday night. Owner Arthur Blank and general manager Rich McKay were scheduled to hold a news conference Wednesday.

There was no immediate word on who would take over for the team's final three games, though defensive coordinator Mike Zimmer and offensive coordinator Hue Jackson would be the most logical candidates.

Petrino did not answer calls placed to his cell phone and his Atlanta-area home. His brother, Falcons receivers coach Paul Petrino, declined comment when reached on his cell phone.

"I don't think I can say anything about it right now," he said. "I'm sorry."

Just two weeks ago, Bobby Petrino said he had no interest in any of the high-profile college jobs that had opened up, and he apparently told Blank in recent days that he would be staying with the Falcons.

"I haven't given it one bit of thought," Petrino said Nov. 26. "I certainly don't want to get into any speculation and rumors and having to deal with that. I'm focused on our football team here."

Petrino was the latest college coach to flop in the NFL.

Steve Spurrier quit after two mediocre years with the Washington Redskins. Nick Saban made it through just two seasons with the Miami Dolphins before returning to the college ranks at Alabama. Of course, they look like long-term hires next to Petrino, who abandoned the Falcons without even making it through one year.

After losing Vick, Petrino tried three quarterbacks without success. The Falcons have lost four straight, all by double-digit margins, and are assured of the 32nd season of .500 or worse in their 42-year history.

"Anytime you're without one of the best athletes in the National Football League, it's going to be tough," cornerback DeAngelo Hall said earlier in the season. "Take Peyton Manning from the Colts, and they'll go through a little slump."

Petrino's stint was one of the shortest for a non-interim coach since the 1970 NFL-AFL merger. Pete McCulley was fired after starting out 1-8 with San Francisco in 1978, and Sid Gillman lasted only 10 games in his second stint as San Diego coach, going 4-6 in 1971 before quitting.

In an interesting twist, Lou Holtz coached the New York Jets for 13 games in 1976. He went 3-10, then left the team with one game remaining to become the coach at Arkansas.

In four years at Louisville, Petrino produced a 41-9 record and some of the highest-scoring teams in the country.

An Atlanta team without Vick was a different story, ranking 24th in total yards and 30th in scoring.

Plagued by injuries on the offensive line, Petrino was forced to start two players who weren't even drafted and just hours after Vick's sentencing in Richmond, Va., Atlanta lost to the New Orleans Saints 34-14. They have lost four in a row by an average of 18.5 points.

"Not a good day," Petrino said afterward.

The resignation had to be a major surprise to Blank, who fired Jim Mora just two seasons after he led the Falcons to the NFC championship game. Before Monday's game, Blank said he felt better than ever about his decision to hire Petrino.

"I feel real fortunate we have a terrific guy leading our team, our CEO, in Bobby Petrino," Blank said. "I think he's proven to me he's a better head coach than we thought he was going to be, dealing with a set of cards we didn't see unfold this year, which probably never in the history of the NFL has anything like this happened. Bobby has done a wonderful job dealing with all of these issues. He's kept the players focused."

There were signs of dissension, however, in particular because of the way Petrino dealt with his players.

To some he seemed aloof, feeling no reason to share personnel decisions with affected players. He could walk through the locker room without speaking to anyone and was openly criticized by two of the team's stars, Pro Bowlers Alge Crumpler and Hall.

A decision to cut nose tackle Grady Jackson, one of the team's most productive defensive linemen, during the bye week drew the ire of veteran players. Quarterback Joey Harrington was noticeably perturbed when, after leading the Falcons to two straight wins, he heard from the media Petrino still considered injury prone Byron Leftwich the starter.

Against the Saints, quarterback Chris Redman made his first start since 2002. While Redman threw for 298 yards and two touchdowns, the Falcons lost again.

After the game, Petrino sounded as though he was still committed to getting the Falcons turned around.

"We'll come back on Wednesday to take a look at it, and then we'll get back to work," he said. "We have to find something to rally around."

Clearly, Petrino already had decided to abandon the sinking ship.