Improved play from the likes of Wilin Rosario (No. 20) and Dexter Fowler (No. 24) have spurred a strong start by the Rockies. (AP)

We’re just three weeks into the 2013 baseball season, barely more than 10 percent of the way through, but already we’re seeing some unexpected performances that could prove to be more than flukes. Here, are 10 of the most unexpectedly positive performances in the early going, five by teams, five by individuals, with a look at what they’ve done and whether or not the nature of those performances is likely to continue as we get deeper into the season. Tomorrow we'll have 10 negative surprises from the first three weeks.

Team Performances

Colorado Rockies: 13-5 (.722), 1st place in NL West

Last year, the Rockies finished in last place, 30 games out of first, with the second-worst record in the National League. Through the first three weeks of the 2013 season, they are tied with the suddenly slumping Braves, who have lost three in a row and four of their last five, for the best record in the NL.

They’ve done this despite minimal roster turnover. Only four members of Colorado's current 25-man roster were not on the team last year, two of those men are bench players (infielder Reid Brignac and catcher Yorvit Torrealba), one (righthanded starter Jon Garland) didn’t play for anyone last year and the last is set-up righty Wilton Lopez, who currently sports a 9.00 ERA.

Of course, that accounting glosses over the healthy returns of Troy Tulowitzki, an MVP-caliber player who lost most of 2012 to a groin injury, and lefty starter Jorge de la Rosa, who made just three starts last year after spending most of the season rehabbing from Tommy John surgery. Both are leading the charge in the early going this season, though even better than de la Rosa has been 25-year-old Jhoulys Chacin (3-0, 1.46 ERA), who just hit the disabled list with a lower back strain.

The Rockies are getting it done on both sides of the ball. Their offense, led by Tulowitzki, Carlos Gonzalez, Michael Cuddyer, Dexter Fowler (team-high seven home runs) and sophomore catcher Wilin Rosario is second in the majors with 5.78 runs scored per game. Their pitching, led by Chacin, de la Rosa (2-1, 2.82 ERA), Garland (2-0, 3.32 ERA) and strong relief work from lefty Rex Brothers and closer Rafael Betancourt (7-for-7 in save chances), has been a tick better than league average in allowing just 4.22 runs per game, a stellar performance for a Colorado staff.

Is it real? The Rockies can hit. They were third in the NL in run scoring last year, and with Tulowitzki back, Rosario a year older and Fowler experiencing a breakout, they should be better this year. The question is, will the pitching hold up? Chacin’s injury isn’t a positive indicator, but de la Rosa posted a 111 ERA+ for the Rockies in the two-plus seasons before his surgery. Garland was a reliably league-average starter before his career was interrupted by shoulder surgery in 2011, and he’s still just 33. There’s certainly the potential for disaster, and while the Rockies are still unlikely to contend all season, it wouldn't be a surprise to see them finish around or even a tick above .500, which would be something close to a 20-win improvement from last year and a major feather in the cap of rookie manager Walt Wiess. They’ll have a major test this week as the Braves come to town for a three-game set starting Monday night.

Boston Red Sox: 12-6 (.667), 1st place AL East

The Red Sox finished last in the AL East last year with the third-worst record in the American League (69-93, .426) and never once got more than five games above .500. This year, it took them just 14 games to get to six games over and prior to Sunday’s doubleheader sweep by the Royals, they had won seven games in a row despite the turmoil their city faced last week. They are fifth in the AL in run scoring and second, behind only the Rangers, in run prevention, and are tied with Texas for the best record in the junior circuit. They’ve done all of that despite injuries to David Ortiz, who made his season debut on Saturday with a rousing f-bomb and a pair of singles, intended shortstop Stephen Drew and starter John Lackey, who looked great for four innings before tearing his bicep, and the early failures of spring training sensation Jackie Bradley Jr and newly-acquired closer Joel Hanrahan (okay, it was just one blown save, but it was really ugly).

Is it real?Clay Buchholz and Jon Lester won’t keep up their current pace (combined 7-0, 1.29 ERA), but if they stay healthy, there’s no reason they can’t both be among the better pitchers in the league, and the rest of the rotation could well improve on its early-season performance, be it due to reinforcements in the form Allen Webster, who made a strong major league debut in a spot-start on Sunday, and Rubby De La Rosa, or from Lackey delivering on the promise of those first four innings. The bullpen could well even out and maintain the same performance, and the offense should be able to at least hold the line with Ortiz back in the fold and Bradley back in the minors given that Will Middlebrooks hasn’t done much other than hit four home runs and Dustin Pedroia’s power hasn’t shown up yet. Injuries have been Boston's bugaboo the last few seasons, and there’s always that risk, particularly with the aged Ortiz and fragile Jacoby Ellsbury, Lackey and Mike Napoli around, but if the Sox can stay healthy, they could well be for real.

New York Mets offense: 5.82 runs per game, best in majors

Only four NL teams scored fewer runs than the Mets last year, and one of them, the Astros, is no longer in the league. So how, after spending the winter failing to fill a largely empty outfield, have the Mets become the major’s most dangerous lineup this April? It’s largely the work of four men: David Wright (of course), leftfielder Lucas Duda, catcher John Buck and second baseman Daniel Murphy (though utilityman Justin Turner has helped out off the bench) and some well-timed hits (New York has hit .310/.400/.503 with runners in scoring position, which works out to an adjusted OPS 44 percent better than the league-average in those situations).

Is it real? David Wright’s .311/.447/.557 performance isn’t out of line with his ability. That’s real. Duda, who is hitting .273/.475/.659, has legitimate power and has shown improved patience. He’ll have his slumps but could indeed have a career year in this, his age-27 season. Buck, whose time keeping the catching position warm for Travis d’Arnaud has been extended by d’Arnaud’s broken foot, has established power, too, but the 32-year-old’s team-best seven home runs are already a third of the way to a new career high. Maybe he could have another season like his career-best 2010 (.281/.314/.489, 20 HR), but even that seems unlikely as he’s never hit above .247 in any other season. Murphy can hit for solid averages (.294 career) with some patience and doubles power (41 doubles per 162 games in his career), so his current .348/.389/.576 line isn’t completely out of character, but he does have trouble staying healthy. Ike Davis and Ruben Tejada should perk up to compensate for some of the regression experienced by the others, but the main issue is the clutch performance. The best OPS+ with runners in scoring position last year was the Tigers’ 116. The Mets are at 144. That’s not real.

Oakland A’s offense: 5.26 runs per game, best in AL

The A’s won 94 games and the AL West last year, and though they only scored 4.4 runs per game on the season, they scored 5.2 runs per game after the All-Star break thanks in part to Manager of the Year Bob Melvin’s expert platooning, a big second half from rookie leftfielder Yoenis Cespedes, and some surprising performances from players such as Brandon Moss and Josh Donaldson. Thus far this year, Melvin is still working those platoons and Moss is holding his own, but Josh Donaldson is scuffling, Josh Reddick, who slumped badly down the stretch last season, can’t buy a hit (he’s 3-for-his-last-37) and Cespedes has been on the disabled list for more than a week with a strained muscle in his left hand.

Instead it’s shortstop Jed Lowrie (.382/.462/.632) and team home-run leader Coco Crisp (.328/.434/.703, 5 HR) that are leading the way with help from the platoon bats of lefty Seth Smith (.388/.464/.571) and part-time catcher Derek Norris (.357/.500/.500).

Is it real? The shape of it clearly isn’t. Crisp, who has reached double-digits in home runs once in the last seven seasons with a high of 11, is not a power hitter. Lowrie isn’t going to produce anywhere near that level even if he does manage to stay healthy. Smith and Norris’s small-sample warnings are even louder than those that should be going off throughout the rest of this piece given their part-time exposure. That said, that 5.26 runs per game this season is a match for that 5.2 runs per game in the second half last year. Cespedes has already shown he’s ready to return on Sunday. Reddick should come around. In addition, Chris Young hasn’t gotten going yet, the team’s 125 OPS+ with runners in scoring position isn’t as outlandish as the Mets’ figure and Melvin does have a knack for putting his players in positions to succeed. Oakland won’t be among the league leaders in run scoring if it finishes the season with Crisp and Lowrie as its best hitters, but an above-average performance with Cespedes leading the charge no longer seems so far-fetched.

Pittsburgh Pirates' run prevention: 3.67 runs allowed per game, second stingiest in NL

Pittsburgh's starting rotation of A.J. Burnett, Wandy Rodriguez, James McDonald, Jeff Locke and Jonathan Sanchez doesn’t inspire a lot of confidence. However, while Burnett (2.63 ERA, 13.1 K/9), and Rodriguez (2-0, 0.56 ERA, 0.38 WHIP) are off great starts, the rotation isn’t what has the Pirates among the league-leaders in run prevention. It’s their bullpen and their defense. Pittsburgh's relievers have a combined 2.03 ERA, third best in the majors (behind Atlanta and Texas) in 66 2/3 innings, the third most by any relief corps in the majors (behind Houston and Toronto). Its fielders, meanwhile, have converted balls in play into outs at a higher rate than any other team in the majors, and itslead over the second-place Braves grows even larger when you adjust for the contours of their respective ballparks (using Baseball Prospectus’s Park Adjusted Defensive Efficiency).

Is it real? The Pirates bullpen is talented, but it won’t be able to hold up if manager Clint Hurdle and the starting rotation continue to demand more than 3 2/3 innings per game from it, which is more than any team but the Rockies got from its bullpen over 162 games last year. The defense, however, should benefit from a full season of Starling Marte in leftfield, the addition of Russell Martin behind the plate in place of an aging Rod Barajas, Garret Jones spending even less time in the outfield and the continued maturation of Pedro Alvarez at third base. Last year, the Pirates allowed just 4.16 runs per game. This year, they should shed Sanchez quickly and could call up Gerrit Cole and/or Jameson Taillon by season’s end. Their ability to keep runs off the board is for real.

Player Performances*

*from teams other than those above

Chris Davis, 1B, Orioles

Season Stats: .403/.486/.855, 7 HR, 21 RBI

Davis leads the majors in OPS, OPS+ and slugging and the American League in all three triple-crown stats (batting average, home runs, RBIs).

Is it real? The power is. Davis has averaged 30 home runs per 162 games in his major league career and hit 33 for Baltimore last year in 139 games. He won’t hit the 63 home runs he’s on pace for right now, but even 40 wouldn’t be terribly out of character for a hitter with his raw power in his age-27 season, particularly given that he only needs 33 more in 144 games to get there. Given that Miguel Cabrera led the league with 44 homers last year, that would put Davis in the fight for the home-run title. Don't expect him to compete in the other categories he’s currently leading, though. Davis is a hacker who has hit .264 in his career, and the man he has driven in the most this season, after himself, is Adam Jones, another hacker off to a hot start who owns a career .324 on-base percentage.

Brandon Crawford, SS, Giants

Season Stats: .317/.403/.524, 3 HR, 13 R, 166 OPS+

The Giants’ good-field, no-hit shortstop has been San Francisco's best hitter this season.

Is it real? No. Crawford hit .288/.351/.409 last September, which was his best performance in any single month of his major league career, not counting his five-game debut in May 2011. He hit .266/.331/.403 in his minor league career, and scouts have never seen him as much more than a glove-first shortstop. He’s 26, so it’s not as though he has a ton of untapped potential at the plate. He hit just four home runs in 143 games last year. That September line above represents his upside. If he is able to do that over a full season it would be a surprise and a dramatic improvement over his first two major league seasons. What he's done thus far is a complete fluke.

Paul Maholm, LHP, Braves

Season Stats: 3-1, 1.03 ERA, 0.87 WHIP, 8.5 K/9, 3.13 K/BB, 4 GS

Maholm didn’t allow a run in his first three starts this season, turned in a quality start in the fourth and has been one of the majors’ best pitchers despite a long track record of mediocrity.

Is it real? In his first six seasons with the Pirates, Maholm posted a 4.48 ERA (95 ERA+) and 1.45 WHIP while striking out just 5.6 men per nine innings, good for a 1.83 K/BB ratio. He’s shown steady improvement over the last two seasons, however, posting a 3.66 ERA (102 ERA+) and 1.29 WHIP for the Pirates in 2011, pushing his strikeouts above 6.0 per nine innings with the Cubs early last season, then having a strong stretch run for the Braves after a deadline deal sent him to Atlanta, posting a 113 ERA+, 1.19 WHIP and striking out 7.7 men per nine innings (with a 3.11 K/BB) over his final 11 starts of 2012. Though his current ERA and WHIP are clearly the result of a small sample, his strikeout numbers seem to be continuing that trend, suggesting that the 30-year-old Maholm, who has added a slow curve that can dip below 60 miles per hour to his repertoire this year, could be maturing into an above-average crafty lefty.

Ervin Santana, RHP, Royals

Season Stats: 2-1, 2.48 ERA, 1.07 WHIP, 8.1 K/9, 5.20 K/BB, 4 GS

The erratic Santana was one of MLB's worst starters last year, posting a 5.16 ERA (73 ERA+) and allowing a major league worst 39 home runs, but the Royals saw something in him, acquiring him and $12 million of his salary at the end of October, and have thus-far been rewarded.

Is it real? Santana was an All-Star and the recipient of some down-ballot Cy Young votes in 2008 when he went 16-7 with a 3.49 ERA (127 ERA+) and 214 strikeouts (8.8 K/9, 4.55 K/BB), but failed to live up to that performance in the intervening four seasons amid eroding velocity, never once striking out more than seven men per nine innings or posting an ERA+ better than his 111 mark in 2011. He is still primarily a fastball/slider pitcher and the average velocity of the former has dipped below 92 miles per hour this season, but he has brought back the sinker he abandoned last year, his home runs per fly ball rate has regressed (though that is likely due to the fact it couldn't have stayed as high as it was last year regardless of what he did) and his peripherals in the early going speak loudly, as does his strong performance against the Red Sox at Fenway Park Sunday afternoon (7 IP, 6 H, 2 R, 0 BB, 7 K). Santana is a notoriously erratic pitcher, so don’t expect him to keep this up all season, but certainly his outlook for 2013 is far sunnier than it seemed coming into the season.

Justin Masterson, RHP, Indians

Season Stats: 3-1, 1.67 ERA, 1.11 WHIP, 8.3 K/9, 2.78 K/BB, 4 GS

Masterson’s apparent break-out year in 2011 instead looked like a fluke after a 2012 that largely echoed his lousy 2010 with a 4.93 ERA (79 ERA+), 1.45 WHIP and 1.81 K/BB ratio, but the see-saw has tipped back yet again in early 2013 as Masterson has looked more like the 2011 model.

Is it real?