Spring Training is approaching, and I'd like to take stock of the offseason so far. Keeping in mind that there are a ton of free agents still available, here are the five teams I think improved themselves the most this winter.

Mets: The Mets made the most audacious and best power grab in the weak National League this offseason, beating out the Diamondbacks (Dan Haren) and Cubs (Kosuke Fukudome). They swindled a desperate Twins team to grab Johan Santana and immediately become the team to beat in the NL. Oh yeah, they did give away Lastings Milledge for a fourth outfielder and a backup catcher. I don't really like the idea of signing Luis Castillo to a four-year deal, either. But when your team grabs Santana for a bunch of B-grade prospects and becomes the best team in the league, you can even forgive bad transactions like those.

Nationals: The Nats aren't going to be very good next year, it's true, but GM Jim Bowden has improved to the point that he might actually be one of the better GMs in baseball, and more importantly, the Nats showed that they have nothing to do with those pathetically short-sighted and frugal last few Expos teams. They swindled a very high-upside talent from the Mets (Milledge - see above), then grabbed another very talented (though clearly insane) player in Elijah Dukes for next to nothing. And most importantly, their farm system is finally in good shape - Baseball America recently ranked Washington the ninth-best organization in baseball after ranking it dead last in 2007.

A's and Orioles: For the A's, rebuilding was just business as usual. For the Orioles, it's long overdue. But both teams wisely took stock of the ridiculously high level of competition in the American League and did a decent job trading stars and building for the future. The Orioles' trade of Miguel Tejada to the Astros wasn't inspiring, but the haul they got for Erik Bedard was great - Adam Jones should team with Nick Markakis to make the Orioles' outfield one of the most exciting young trios in the league (even though 30-year-old Luke Scott should be the other starter), and Chris Tillman and Tony Butler are exciting pitching prospects. The A's took advantage of the Diamondbacks' outstanding minor league depth to grab a ton of young talent for Dan Haren, then shipped Nick Swisher to the White Sox for a couple of high-upside arms. It's not that either of these teams really ripped anyone off (well, the A's did get a real ballplayer for Mark Kotsay, which is pretty excellent), but both score big points for having a clear, unambiguous plan. Both the A's and Orioles are going to be bad next year, but sometimes discretion is the better part of valor, and when the talent level in the AL levels out a bit, these teams will be waiting. Well, the A's will, at least.

Tigers: If you're going to try to compete in the ultra-talented American League, this is how you do it - by adding a 24-year-old superstar, a good shortstop, and a solid starting pitcher to an 88-win team. Detroit paid a steep price for Miguel Cabrera, Edgar Renteria and Dontrelle Willis - the Marlins should be thrilled to have Cameron Maybin and Andrew Miller in their organization, and Gorkys Hernandez will be an interesting prospect to watch for the Braves - but the Tigers were, and are, built to win now. With Cabrera under control through 2009, they'll get two shots at winning a World Series with one of the best offenses in recent memory. And, since they don't care for Major League Baseball's draft slotting recommendations, they'll have their farm system back in shape in no time.

Also receiving consideration: Padres, Diamondbacks, Cubs, Brewers.