The reasons why people are buying into Vince Young now are as obvious as the reasons most people didn't coming into this year. After two years as a sub-par (and regressing) passer landed him on the bench he's returned to the starting lineup and the Titans have gone from 0-6 to a playoff possible 5-6. He's also played the best football we've seen from him since his days at Texas.
But I still have some reservations.
There's no denying that VY is playing some very good football at the moment. Young currently ranks 8th in the league in passing DVOA! (Football Outsiders' per play value stat). PFR's ANY/A+ (Adjusted Net Yards per Attempt scale to a OPS+ like scale where 100 is average, 110 is 10% above average, etc) rates his season to date at 115. That's the same as Tom Brady's career rating. The issue is obviously sample size, the immortal Todd Collins put up a ANY/A+ of 136 (just a touch above Drew Brees' season to date) over 105 attempts in 2007. Vince has 132 attempts so far this year. If he doesn't regress to the mean hard (like Todd Collins did in the 2007 playoffs) then his rebirth as a NFL starter will be undeniable, but the sample isn't big enough for any ass crowning yet.
My second reservation is that crediting VY with the Titans turnaround ignores 3 factors that are much more important in my mind.
1. The Titans are leaning harder on Chris Johnson.
Over the Titans 6 game losing streak Johnson touched the ball 111 times. Over the 5 games with VY under center he's gotten 139 touches. 28 more touches in one less game. That putting the ball in your teams best players hands more often led to more wins shouldn't shock anyone. It could be argued that the winning led to the running, that doesn't seem to be the case given that poor LenDale's workload has decreased since the QB change.
2. The defense is playing defense.
The Titans D allowed less than 20 points just once in the first 6 games, in the last 5 they've only given up more than 20 once. Even without counting the beatdown the Patriots laid on the Titans D they are allowing 9 points per game less over the last 5 games than over the first 5 (with the Pats game included the difference is 15 per game).
3. The schedule has softened.
The Titans divisional games against the Jags and Texans show legitimate turnaround, but in the remaining 5 games the Titans started off rough losing to the Steelers, and Jets (with Kris Jenkins edition), hit rock bottom at the toughest point in their schedule against the Colts and Patriots, and they have rebounded while playing the Warner-less Cards, the Bills and the Niners. That doesn't look like a coincidence to me. The Titans successes and failures in non-division games map pretty well to the strength of their opponent. Not a surprise, but something that hasn't really been picked up on too much in the popular storyline.
Vince Young has played extremely well so far this year, anyone that tells you different hasn't followed him this year or has a serious bias. However, at this point it's important to remember that ultimately substandard QBs have put up numbers this great in these size of samples before and that a lot of other factors have played into the Titans turnaround beyond the change of faces at the most recognized position.