CHICAGO CUBS

Prospect Star Of Camp: Tyler Colvin was supposed to get a spring training cameo before heading to Triple-A. But a .459/.459/.716 line has completely changed the Cubs' timetable. Colvin has been the star of camp and has played his way onto the Opening Day roster and even into splitting time in the outfield so that he can start two to three days a week. There are still plenty of reasons to be concerned about whether Colvin is ready for the big leagues–he's shown no improvement in his free-swinging ways, drawing no walks in spring training—but his improved strength and power has shown the Cubs' enough to anoint him as one of the cornerstones of the team's future.

Keep An Eye On: Shortstop Starlin Castro (.433/.452/.667) made a strong argument for making the Opening Day roster as well, but considering he has 31 games above Class A, it makes sense that he will return to the minors for more seasoning.

A Rough Spring: Lefty John Gaub had a chance to make the Cubs' roster as a reliever, but he didn't really make much of an argument in Arizona. Gaub struggled with home runs and his command on the way to a 1-0, 7.04 before being sent back to the Triple-A Iowa roster.

CINCINNATI REDS

Prospect Star Of Camp: Aroldis Chapman arrived in Reds camp with great fanfare, but he not only managed to live up to the hype, he actually proved to be better than expected. The 100 mph fastballs Chapman throws are shocking because of the rarity of seeing a lefty hit 100, but that was something everyone had already seen at the 2009 World Baseball Classic. His control and secondary stuff (which includes a 90 mph slider) have been better than expected, although a back injury did slow him down in the final weeks of spring training. Chapman's biggest adjustments will continue to be off the field, where he has to adjust to an entirely new environment.

Keep An Eye On: The Reds fifth starter's job looks to be coming down to a battle between a pair of rookies. Righthander Mike Leake, last year's first-round pick, has a 3.00 ERA in 18 innings while lefthander Travis Wood has also impressed. Leake hasn't even pitched in a minor league game yet, but if the Reds choose solely based on spring training he's been the most impressive. It's worth remembering that this is a team that went more than a decade without developing a solid homegrown starting pitcher. Now Cincinnati has Johnny Cueto and Homer Bailey in the rotation with Chapman, Wood and Leake fighting for the fifth spot. Juan Francisco still doesn't walk, but he keeps on hitting which has kept him in the battle for a backup infield spot.

A Rough Spring: Matt Maloney came into spring training as the leader for the fifth starter's job, but an 8.64 ERA this spring had the team looking at moving him to the bullpen. Yonder Alonso didn't have a chance to make the big league roster, but .125/.125/.188 numbers helped speed his return to the minors.

HOUSTON ASTROS

Prospect Star Of Camp: Righthanded reliever Sammy Gervacio impressed the Astros in a callup last summer, and he's carried that success over into spring training. Thanks in part to an awkward delivery, Gervacio has struck out 15 while allowing only seven baserunners (five hits and two walks) in 11 innings this spring. In a relatively unsettled Astros' bullpen there is room for Gervacio to move into a more prominent role if he keeps pitching like he's been pitching.

Keep An Eye On: Third baseman Chris Johnson, the Astros' No. 16 prospect, has hit his way onto the Opening Day roster with a .302/.383/.736 spring. He'll have to keep hitting as the Astros will be looking for a roster spot for Lance Berkman when he returns from the disabled list in the not-too-distant future. Catcher Jason Castro didn't make the club out of spring training, but he did impress in extensive action and reinforced the feeling that he will be back before too long.

A Rough Spring: A year ago Brian Bogusevic was one of the stars of the Astros' farm system thanks to an quick transition from pitching to the outfield. But the long season exposed some of Bogusevic's weaknesses, and he didn't do much to alleviate those concerns in a short stint in big league camp. Bogusevic will have to hit for more power to be a big leaguer, but a .071/.071/.143 line in 14 at-bats didn't give him a chance to make much of an impression this spring.

MILWAUKEE BREWERS

Prospect Star Of Camp: The Brewers love lefthander Zach Braddock's arm, and he was outstanding all spring, tossing eight innings without giving up an earned run. He struck out eight and walked none. The Brewers' No. 7 prospect wrapped up last season in Double-A Huntsville and pitched in the Arizona Fall League, so he's not far away from being able to help in Milwaukee.

Keep An Eye On: Righthander Jon Axford also threw well and hard in spring training, save one poor outing. He struck out seven in nine innings and should work his way into the bullpen mix again after flashing his ability in seven September big league outings last season.

A Rough Spring: Last year's top rookie, 27-year-old Casey McGehee, had to raise some doubts with his .172/.224/.238 line this spring, which included 12 strikeouts in 58 at-bats. McGehee attributed his slow spring to not playing winter ball this offseason and knee surgery, which threw off his timing. His struggles could open an opportunity for prospect Mat Gamel, but he's out with a shoulder injury.

PITTSBURGH PIRATES

Prospect Star Of Camp: He's not a conventional prospect, but 27-year-old Daniel McCutchen will get a crack at the big league rotation after a solid spring, earning the No. 5 spot. He walked just three in 13 1/3 innings and struck out 10.

Keep An Eye On: Neil Walker started his pro career as a catcher, and the 2004 first-round pick soon moved to third base. He played some outfield this spring before being sent back to Triple-A for his fourth stint at that level, and he's being groomed as more of a utility player. He went 5-for-16 this spring and walked (4) as often as he struck out (4). If he can sustain that improvement, he'll become a useful big leaguer.

A Rough Spring: Jason Jaramillo's bat has held him back, and he hit .192/.192/.308 in 26 at-bats this spring, with no walks. However, he earned the backup catcher job over minor league vet Erik Kratz by virtue of already being on the 40-man roster.

ST. LOUIS CARDINALS

Prospect Star Of Camp: Manager Tony La Russa isn't known for his patience with young players, but two of the Cardinals' top five prospects earned starting jobs this spring. 3B David Freese overcame five errors, an offseason DUI and the late addition of veteran Felipe Lopez to claim the starting job at the hot corner, and lefthander Jaime Garcia continued his strong comeback from Tommy John surgery to earn a rotation spot. Garcia, 23, posted a 1.93 ERA in 18 2/3 innings this spring, striking out 16 and walking five.

Keep An Eye On: Fernando Salas, 24, dropped out of the Top 30 after his 2009 season but put himself back on the prospect map this spring, striking out 10 and walking only one in 8 1/3 innings of spring camp. He doesn't have overwhelming stuff, but he throws strikes, which endears relievers to all managers.

A Rough Spring: Mitch Boggs was making a play for a bullpen spot, but he gave up an alarming 18 hits and nine runs in 11.2 innings. To his credit, he did strike out 12 and generally was around the strike zone, but the Cardinals don't have great depth behind last year's surprise closer, Ryan Franklin.