[jtg33]

My nomination would go to the 2001 Seattle Mariners:

- Hosted the 2001 All-Star Game (8 Mariners were on the AL squad)
- AL-record 116 regular season victories
- Ichiro Suzuki wins the AL Rookie of the Year and the AL MVP
- Lou Piniella wins AL Manager of the Year
- 3-0 sweep of the Chicago White Sox in the first round
- 4-1 loss to the Yankees in the ALCS

The Mariners destroyed just about everybody in their first 165 games, but in their last five they were completely demolished by a Yankees team that went on to lose to the Diamondbacks in seven in the 2001 World Series.

This doesn't really count as a nose-dive, since the Mariners were a great team all the way up to the ALCS, but they were absolutely taken apart by the Yankees. 2001 was never said to be Seattle's year, but the way they'd played for 6 1/2 months, it should have been their year, and it wasn't.

It only took them five games to collapse and to have their title dreams dashed, but those five games were all the Yankees needed to get it done.

But that's just my two cents.