Can you feel it in the air? The breezes are getting a little warmer, the snow is beginning to melt, and the optimistic chirping of birds would be audible if not for the sound of thousands of busted brackets being torn up and thrown away. That’s right: it’s late March, arguably the most excitement-packed few weeks in the entire sporting calendar. The Cinderellas of the NCAA College Basketball Tournament may be stealing the spotlight now, but that excitement is easily matched by the anticipation that MLB fans feel leading up to Opening Day, which this year will fall on Mar. 31. Before the 2013 season kicks off with the Texas Rangers welcoming the Houston Astros into the American League, let’s take a look at what to expect from the Astros’ former home, the National League. (Coverage will continue next week with a full preview of the American League.)

NL West

The team to beat in the National League West division is, by default, the defending World Series Champion San Francisco Giants. Rather than messing with the success, the Giants front office directed most of their offseason attention towards retaining players from last year’s squad, with the only key loss being steroid culprit Melky Cabrera. While the Giants were content to admire their shiny new trophy over the course of the winter, their archrivals the Los Angeles Dodgers kept busy by adding to their already outrageous roster. The Boys in Blue dropped major cash on Zach Greinke, Brandon League, and South Korean import Hyun-jin Ryu, adding three large contracts to what will be the highest MLB payroll of all time. With a batting order featuring Matt Kemp, Hanley Ramirez and Adrian Gonzalez, the Dodgers will be tough to beat if they can stay healthy.

The other three teams in the West, the Arizona Diamondbacks, Colorado Rockies and San Diego Padres, will probably struggle to keep up with their peers, although the D’backs certainly should not be overlooked. The team traded away star outfielder Justin Upton but picked up super-utility man Martin Prado as well as a handful of former Oakland A’s, including Brandon McCarthy and Cliff Pennington. The Padres, meanwhile, will hope that infielder Chase Headley can have another monster year, but even if he does, their roster still has a few too many holes to contend. The same goes for the Rockies, whose only major move this winter was to make Walt Weiss their new manager.

NL Central

The National League Central division got better simply by the subtraction of the basement-dwelling Astros, but otherwise the pecking order of the division remains mostly unchanged. The Cincinnati Reds are still front-runners despite making only one significant offseason move, swapping outfielder Drew Stubbs to the neighboring Indians in exchange for Shin-Soo Choo. The St. Louis Cardinals also had a quiet winter, although they lost free agent starter Kyle Lohse to the division rival Milwaukee Brewers. The Cardinals exceeded expectations by making the postseason in 2012, and if they expect to repeat they will need a full season from ace Adam Wainwright, especially after losing Chris Carpenter to a shoulder injury. Wainwright recently signed a 5-year, 97.5 million dollar extension, meaning that the Cards are certainly banking on his ability to stay healthy.

The aforementioned addition of Lohse is the only marquee move for the Brewers, who failed to construct any kind of supporting cast around star outfielder Ryan Braun. If continued allegations of steroid use hamper Braun’s performance, the Brewers could quickly slide from a mediocre team to a bad one. This would open the door for the Pittsburgh Pirates, who overachieved in 2012 but faltered down the stretch for the second straight season. The Pirates dropped questionable sums of money on catcher Russell Martin and Francisco Liriano, the injury-prone former Twin, moves that seem unlikely to have much of an effect. Still, Pittsburgh’s rotation was surprisingly good last year, and they still have one of the best young players in the game in Andrew McCutchen. And then there are the Chicago Cubs, lovable losers of Chicago’s north side. Despite picking up pitchers Edwin Jackson and Scott Baker, another former Twin, the Cubbies are still a long ways from contention. Sorry.

NL East

The East division could be the strongest in the National League, even with the defending champs residing in the West. The Washington Nationals are the likely favorites after adding Dan Haren to a starting rotation that already features young stars Stephen Strasburg and Gio Gonzalez. The team also added flame-thrower Rafael Soriano to their bullpen and improved their outfield defense by adding ex-Twin Denard Span in place of Michael Morse. The Atlanta Braves should give the Nationals a run for their money, however, after picking up the outfielding Upton brothers, B.J. and Justin. The team lost Michael Bourn and Martin Prado, however, and their rotation is still a point of concern even after Kris Medlen’s outstanding 2012 performance. Craig Kimbrel may be the best reliever in the game right now (sorry Aroldis and Mo), so the Braves will be in good shape if they can carry leads into the ninth inning.

The Philadelphia Phillies still have two of the best starters in the game in Roy Halladay and Cliff Lee, but their offseason pickups of Delmon Young and Michael Young do little to inspire confidence. Former Twin Ben Revere is a talented young player, but he will have big shoes to fill for the Phils outfield after Shane Victorino left in 2012. If Chase Utley and Ryan Howard have healthy 2013 seasons, the Phillies could still contend, but it will be tough for them to surpass the Nats.

Last but not least are the New York Mets and Miami Marlins, both of whom will be unable to keep up with the level of play in their division in 2013. The Mets lost R.A. Dickey but did add former Blue Jays ace Shaun Marcum, and also made improvements to their farm system. And then there are the poor, poor Marlins. Only a year removed from the unveiling of the team’s new spectacle of a stadium, owner Jeffrey Loria decided to hemorrhage any semblance of talent on the team and begin a ground zero rebuilding project. Marlins fans will have to hope that this overhaul will lead to a World Series title in the near future, just as it did in 1997 and 2003. However, 2013 will definitely not be a fun year for the Florida Fish.