First, the Tigers have home field advantage, which you can never doubt the importance of. After splitting games on the road, the Tigers won last night in Comerica Park, 5-4.
The Tigers also have a favorable pitching matchup. While Rick Porcello isn't all that great, he surely beats out the Yanks A.J. Burnett. Porcello finished the season with a 14-9 record, and a 4.75 ERA.
Burnett finished with an 11-11 record, and an ERA of 5.15. A.J. Burnett is a very streaky pitcher, who the Tigers shouldn't have much trouble. Burnett is the Yankees last prayer, and they'll need to pray for him to do well. In his 32 starts this season, Burnett only turned in 10 quality starts. A quality start is going at least six innings while only giving up three runs.
Porcello shouldn't have too hard of a time, especially with all the cold hitters the Yankees have in their lineup. Porcello's only problem is facing lefties. Lefties are hitting .321 off him. On the other hand, right-handed hitters are hitting .248 on him.
Three of the Yankees top hitters, A-Rod, Robinson Cano and Mark Teixeira went a combined 0-10 in the last game. In fact, A-Rod and Tex are a combined 1-21 in the series so far. Talk about cold.
Despite his last few outings being rocky, Jose Valverde hasn't blown a save in 49 attempts this season. I doubt he plans to start now. If need be, I'm sure he would be able to close out the Yankees in the ninth inning.
Finally, another thing you can't overlook is momentum. The Tigers have the momentum, after winning two games in a row in the series, even one at Yankee Stadium. Sure, the Yankees want to keep their season alive, but they'll have a hard time of it.