I know, we're hours away from the 2010 season starting but here I am looking back one last time at the 2009 team for some analysis. Many Pats fans were surprised by the pick of Devin McCourty but after sifting through Pro Football Focus' pass coverage numbers it seems pretty clear that adding a top flight corner was absolutely necessary.

My findings after the jump...

You can waste away a good portion of your life browsing though all of ProFootballFocus.com's stats and they recently added all their pass coverage numbers. Here are the 2009 Patriots Defensive Back rankings from best to worst (lower is better, click the ratings to go to the corresponding stats page):

Leigh Bodden 59.7 - Bodden was obviously the best Patriot DB, you didn't need stats to tell you that, but he was clearly hard to consistently throw on despite giving up four touchdowns. Teams threw at him more than anyone (probably  because he was the only consistent starter so seeing a lot of passes was inevitable) but he still only gave up catches 50% of the time. That was better than every other Pats DB.

Brandon Meriweather 64.7 - The stats confirm Meriweather had a horrid day versus New Orleans, that long TD was his fault but it was the only one he gave up last season according to these rankings. I actually feel better about Meriweather after seeing these stats. His inconsistency isn't as glaring here as it was on the field. A little improvement could really put him into the top five safeties in the NFL. 

Darius Butler 67.4 - the stats confirm Patriots fans have reason to be excited about Butler. He was targeted a lot in the second Miami game but held his own. Only once did his ranking go over 100 in a game, best on the team. Clearly the team brought him along slowly, but I'd feel good about seeing him as a starter.

Shawn Springs 90.5 - These numbers make it a little more clear why Springs didn't see much action in the middle part of the season. Both Baltimore and Denver went after him and had a lot of success.

James Sanders 105.6 - Kinda surprising to see the "steadying force" ranked so badly in coverage huh? He didn't have a big sample size, but these numbers make me wonder if Sanders could be on the bubble.

Brandon McGowan 114.8 - This is exactly what you thought, he's a run stopping safety, he wasn't thrown at a lot but when he was it wasn't pretty. Being so one-dimensional cold spell danger for him.

Jonathan Wilhite: 115.3 - Even I didn't think the stats would show a disaster this bad for Wilhite. The only good games he had were when teams didn't throw at him. He gave up more TDs than any other DB, and really had only one good game when teams did throw on him, the second Buffalo game.

Patrick Chung really didn't have enough of a sample size to include him here, but it's pretty clear that there's a need for a safety who can cover as well as play at the line of scrimmage. If Chung can prove better in coverage than Sanders and McGowan (which doesn't look too hard) he could be your day one starter next to Meriweather.

It's even clearer to me now that Jonathan Wilhite might be a dime back at best and this team badly needed a third corner, more than even Patriots blogging gurus like myself thought. Hopefully McCourty is the answer. If he and Chung can rise to the occasion this season the Patriots defensive backfield should be excellent for years to come.

And finally, because I know you're wondering, here are the coverage rankings for Darrelle Revis (29.1, that's right 29.1), Anotonio Cromartie (72.0) and Asante Samuel (79.3).