A lot of it had to do with the fact that the Tigers live and die by the longball and when that stopped or there was no one on when they did hit one they had no other offensive tools. National League teams are better equipped to play the small ball that can come into play in series that feature great pitching and low scoring games because they are used to bunting, pitchers batting, the double switch, and having rosters that are built for that kind of baseball. Sometimes the AL teams can't even use one of their best offensive players due to the DH not being used at times.
Believe me, there are not a ton of teams that want Delmon Young on their roster and just having him in the lineup shows that the Tigers have a weakness that can be exploited. He is a horrendous offensive and defensive player.