I think the thing that annoys me the most when we get around to selecting a Most Valuable Player is the number of folks who cast their votes for the best player rather than the most valuable. To me, the MVP has to be the one who has the biggest impact on his team's success and who would be missed the most if injured or lost.

Having brought you the Pro Football Weekly Midseason All-Pro team last week, I've spent some time in recent days pondering who the Most Valuable Player in the NFL has been over the first half of the 2009 season.

Chris Johnson had a phenomenal first half and is an easy choice as the best running back in the league, with Cedric Benson second and Adrian Peterson and Steven Jackson right behind Benson. But would the Titans' first half have been all that different without Johnson, or has Jackson's performance been enough to change the fortunes of the Rams? Clearly, Peterson has made huge contributions to the Vikings, but is he the biggest contributor on his own team? Would the Bengals be where they are without Benson? They may find out if Benson's Week 10 hip injury limits him in the second half of '09.

The Giants' Steve Smith, Arizona's Larry Fitzgerald, Indianapolis' Reggie Wayne and the Texans' Andre Johnson all have been game-changers at wide receiver, but none enough to qualify as an MVP. In fact, all are replaceable — if not with 100 percent efficiency, certainly at the 75-90 percent level. I might argue that Vincent Jackson and Chad Ochocinco have been the most valuable receivers the first half of this season, but neither is an MVP candidate.

Not only are Brett Favre, Peyton Manning, Ben Roethlisberger and Tom Brady among the top eight rated passers in the NFL, all four are legitimate first-half MVP candidates. Drew Brees, who is ranked second in passer rating, and Aaron Rodgers, who is fourth, are not. Brees turned the ball over 10 times from Weeks Seven to 10, yet the Saints won all four games. He's had great games and mediocre ones, and the Saints keep on winning. What has Rodgers done for his club? With chances late in both Vikings games and the Bucs contest to lead his team to victory, Rodgers couldn't get it done.

Ryan Clady, Jake Long, Andrew Whitworth, Michael Roos, Jahri Evans and Nick Mangold have all had All-Pro seasons, but an offensive lineman will never win a leaguewide MVP award. In the ultimate team sport, offensive linemen are most dependent on each other, timing and teamwork, and one player can't make an entire line successful.

On defense, Troy Polamalu is an MVP, but we've learned that as much from the time he's missed as from the games he's played, and he missed too many games this season to be strongly considered. Jared Allen, Dwight Freeney and Elvis Dumervil are having MVP-type seasons and are top candidates for Defensive MVP. But I don't think they've done enough to be considered along with Benson, Favre, Manning, Roethlisberger and Brady for the award — the one guy who's meant the most to his team's success and without whom his club would be lost.

The Vikings are a Super Bowl contender with Favre and were not without him. But the huge contributions of Peterson and Allen are impossible to ignore and probably cause the three to cancel each other out. Equally unfair is the fact that as close to 100 percent as Brady appears to be, the success Matt Cassel had in his place last year suggests he is, in fact, replaceable. And while Roethlisberger clearly is key to the Steelers, they've also won when he's played poorly.

What separates Benson and Manning in this group is how clear it is that each of their teams, legitimate Super Bowl contenders at the halfway point, would not be anywhere near the spots they're in without them. Forced to make a choice, as impossible as they are to split, I have to go with Manning for now. I guess that's the difference between 9-0 and 7-2.

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