1. Daisuke Matsuzaka: had a mediocre year in 2007, going 15-12 with a 4.40 ERA. Was this due to the transition from the Japanese Leagues to MLB, or is he really just an average pitcher? 2008 will be key in determining whether he is ace material, a pressing question for the Red Sox given Beckett's latest injury and Schilling's uncertain future.
2. Lastings Milledge: his trade to the Nats angered the more stat-savvy contingent of Mets fans (especially those at Blastings! Thrilledge). It's already an explosive enough situation in Flushing following last year's September collapse, and if Milledge stars in Washington, things will only get hotter.
3. Livan Hernandez: looking to be the Twins' opening day starter, placing him in the unenviable role of succeeding the great Johan Santana. Minnesota will need a strong year from him to stay competitive in the top-heavy AL Central.
4. Jeremy Hermida: Cabrera's trade leaves a gaping hole in the Florida lineup, and the burden of at least trying to replace him will fall to their other young hitters. The Marlins organization has had high hopes for Hermida for a long time, and, having improved significantly from 2006 to 2007, he could be set for a breakout year.
5. The Colorado Rockies: you might remember, before the Red Sox completely dominated them in the World Series, they went on one of the hottest streaks in the history of baseball and in the process won an incredible one-game playoff against San Diego, picked up their first NL Championship, and made Troy Tulowitzki a household name. Their improbable run was arguably the best story of MLB in 2007, and whether they can show themselves to be more than a one-month wonder will be one of the most intriguing stories of 2008.