The New York Giants, who are missing their best defenders from last year's championship team, probably won't be able to defend their title, oddsmakers say.

The Giants open the National Football League season tonight at home against the Washington Redskins as the sixth-favorite bet to win the Super Bowl at 15-1 odds, according to Las Vegas Sports Consultants. The New England Patriots, whom the Giants defeated to win the crown, are 5-2 favorites.

New York won't have its two starting defensive ends from a 2007 team that led the league in quarterback sacks. Seven-time Pro Bowl selection Michael Strahan retired, and Osi Umenyiora, who led the team with 13 sacks, is out for the season with a knee injury. The loss of those players combined with the difficulty of winning consecutive championships made the Giants' odds longer.

"Teams just don't repeat much in the NFL anymore," said Mike Seba, a senior oddsmaker at Consultants, which advises sports books on setting odds. "Then you take into account they're missing their two best defensive players from last year, and it's going to be tough."

The Dallas Cowboys, one of the teams the Giants upset on their way to the championship game last season, have the second- best odds to win the Super Bowl, at 9-2. The Indianapolis Colts and San Diego Chargers, New England's American Football Conference rivals, are the third favorites, at 6-1. The AFC has won four of the past five Super Bowls and eight of the last 11. A winning $10 bet on the Giants at 15-1 would yield a $150 profit.

Umenyiora tore cartilage in his knee during an exhibition game and will miss the season. Strahan, the NFL's single-season sack leader, retired in June after 15 years in the league and opted not to return following Umenyiora's injury.

"You're not talking about just guys that are backups, you're talking about two starters, two Pro Bowlers," said former Washington Redskins quarterback Joe Theismann. "Guys of that quality are very difficult to find. I think it's very, very tough for the Giants."

The Giants responded by moving linebacker Mathias Kiwanuka to defensive end, and signing Jerome McDougle from the Philadelphia Eagles.

The Patriots are the most recent of eight teams to repeat as Super Bowl champions when they won back-to-back titles in 2004 and 2005. New England, which also won in 2002, was a 12- point favorite to beat the Giants in the Super Bowl and win its fourth championship in seven years last season after going undefeated in the regular season and playoffs.

New York won 17-14 as quarterback Eli Manning completed a 13-yard touchdown pass with 35 seconds left to wide receiver Plaxico Burress.

This year, Patriots quarterback Tom Brady and receivers Randy Moss and Wes Welker return for an offense that outscored its opponents by an average of 18.6 points during the team's undefeated regular season.

For that reason, oddsmakers don't expect New England to continue a recent NFL trend of Super Bowl losers missing the postseason the following year. The Seattle Seahawks, who lost the title game to Pittsburgh in 2006, are the only team in the past nine years to reach the playoffs the season after losing the championship.

The Patriots open their season at home against Kansas City on Sept. 7, while the New York Jets and their new quarterback, Brett Favre, play the Dolphins in Miami the same day.

Favre decided to come out of retirement four months after saying his 17-year NFL career was over, and was traded to the Jets from the Green Bay Packers. To make room for Favre, the Jets released quarterback Chad Pennington, who was signed by the Dolphins.

The acquisition of the league's most prolific passer narrowed the Jets' odds of winning the Super Bowl to 25-1, down from 75-1 prior to Favre's arrival.

The Jets are favored by 3 points against Miami, while the Giants are 4-point favorites against Washington. The Super Bowl is Feb. 1 in Tampa, Florida.

Though not favored to with the championship, the Giants shouldn't be overlooked, says their former quarterback and current CBS Sports football analyst Phil Simms.

"The Giants are really good, and I don't know why people think they're not," said Simms, a member of two Super Bowl- winning teams. "I think they will be a better team this year than they were last year. That doesn't mean they'll win the Super Bowl, but in my eyes I'll be very surprised if they're not a better team."