Jean Segura and MLB's 7 Most Shocking 2013 Breakout Stars

The 2013 MLB season has seen some fantastic performances, and while the likes of Miguel Cabrera and Clayton Kershaw putting up fantastic numbers does not come as much of a surprise, there have been some unexpected stars to this point as well.

One such player is Brewers shortstop Jean Segura, who recorded the first six-hit game since August, 11 2009 on Tuesday night, according to a tweet from ESPN Stats & Info.

What follows is a look at the seven most shocking breakout stars of 2013, including Segura. These guys have come out of nowhere to play a vital role in their team's early-season success.

It should be noted that not every breakout season is a surprise. Shelby Miller and Matt Moore are enjoying huge campaigns, but entered the season as two of the game's most highly regarded young arms. Chris Davis is also having a fantastic season, but he, too, enjoyed success last season when he hit 33 home runs.

Those are just a few examples of guys you won't find on this list, but here are the seven guys who do fit the bill of a "shocking breakout star" so far in 2013.

All WAR numbers courtesy of FanGraphs.

Daniel Nava, RF, Boston Red Sox

G	AB	H	HR	RBI	R	BA	OBP	SLG	WAR
46	152	44	6	32	27	.289	.392	.461	0.4

With the Red Sox's offseason signings of Jonny Gomes and Shane Victorino to start alongside Jacoby Ellsbury, it looked as though Daniel Nava would serve as the team's fourth outfielder or perhaps even find himself in Triple-A.

Plucked from the Independent League in 2007, Nava hit .243/.352/.390 with six home runs and 33 RBI over 267 at-bats last season as a key reserve for the team.

Little was expected from the 30-year-old entering this season, but he has been one of the team's best hitters, ranking third on the team in RBI, fourth in runs scored and third in OPS among regulars.

Jeff Locke, SP, Pittsburgh Pirates

GS	IP	W-L	ERA	WHIP	H	R	ER	BB	K	WAR
10	58.2	5-1	2.45	1.14	42	17	16	25	39	0.2

Having seen big-league action in each of the past two seasons, going a combined 1-6 with a 5.82 ERA in 12 games (10 starts), Jeff Locke entered spring training vying for the No. 5 spot in the Pirates rotation.

He won a spot and has not looked back since. The 25-year-old has been as big a part of the Pirates' early-season success as anyone on the roster.

Originally a member of the Braves organization, Locke was acquired in the Nate McLouth trade back in 2009. He ranked as the Pirates' No. 8 prospect in 2010 and No. 10 prospect in 2011, according to Baseball America.

Matt Carpenter, 2B, St. Louis Cardinals

G	AB	H	HR	RBI	R	BA	OBP	SLG	WAR
49	191	59	4	18	41	.309	.394	.455	2.4

After Matt Carpenter hit .294/.365/.463 with 46 RBI in 296 at-bats as a rookie while seeing most of his playing time off the bench as a backup corner infielder and outfielder, the Cardinals decided to try him out at second base this season.

The move has worked brilliantly so far.

While Carpenter has still split his time between second and third base, he has found his way into the everyday lineup and emerged as the team's leadoff hitter.

The 27-year-old has been a terrific catalyst for a potent Cardinals lineup, and his 2.4 WAR ranks No. 14 among all position players to this point.

Edward Mujica, RP, St. Louis Cardinals

G	IP	W-L	SV/OPP	ERA	H	R	ER	BB	K	WAR
23	23	0-0	16/16	1.96	13	5	5	1	21	0.5

Two Cardinals on a list of seven players may seem like a bit much, but their ability to find contributors in unexpected places is a big reason why the team has been so consistently successful over the years and why they currently have the best record in baseball.

The Cardinals bullpen was a mess to start the season, with closer Jason Motte on the DL and his replacement, Mitchell Boggs, struggling mightily.

However, the bullpen has become a strength since the team moved Edward Mujica into the ninth-inning role and flame-throwing rookie Trevor Rosenthal into the setup role.

The 29-year-old Mujica was acquired from the Marlins at the trade deadline last season, and he posted a terrific 1.03 ERA in 29 games after joining St. Louis. Even with that terrific finish to the season, though, it's safe to say no one expected him to emerge as one of the game's top closers.

Josh Donaldson, 3B, Oakland Athletics

G	AB	H	HR	RBI	R	BA	OBP	SLG	WAR
52	191	63	8	33	28	.330	.404	.560	2.7

One of the biggest surprises for last year's Oakland team was the play of Josh Donaldson at third base—though there were legitimate questions as to whether he could hold down the everyday job in 2013.

After hitting just .153/.160/.235 with one home run and seven RBI through June 13, Donaldson was shipped to the minors, where he proceeded to post a 1.000 OPS with 13 home runs and 45 RBI in 51 games.

Upon being recalled, he was a different player and from Aug.14 to the end of the season, he hit .290/.356/.489 with eight home runs and 26 RBI. That was apparently an indicator of bigger things to come, as the 27-year-old has been one of the top hitters in the AL so far this season, and his 2.7 WAR is tied for eighth among all position players.

Patrick Corbin, SP, Arizona Diamondbacks

GS	IP	W-L	ERA	WHIP	H	R	ER	BB	K	WAR
10	68.1	8-0	1.71	1.02	50	14	13	20	56	1.6

Entering spring training, Patrick Corbin was not even expected to be a part of the Diamondbacks rotation, but the struggles of top prospect Tyler Skaggs opened up the No. 5 spot in the rotation for him, and he's run with the opportunity.

Corbin made 22 appearances (17 starts) as a rookie last season, going 6-8 with a 4.54 ERA in 107 innings of work. Decent numbers for a 22-year-old, but nothing that would have made anyone think he'd be a Cy Young candidate this season.

That's exactly what he's been, though, as the left-hander leads the NL in wins and is tied for second in ERA. He allowed more than two runs in a start for the first time his last time out against the Padres, but he still turned in a quality start and earned the win.

Jean Segura, SS, Milwaukee Brewers

G	AB	H	HR	RBI	R	BA	OBP	SLG	WAR
49	197	72	8	22	30	.365	.400	.569	2.7

With his six-hit game on Tuesday night, Jean Segura pulled into the NL batting-title lead with a .365 average, and he currently leads the Senior Circuit with 72 hits.

Acquired from the Angels last season in the Zack Greinke trade, Segura entered 2012 as the No. 55 prospect in baseball, according to Baseball America, but he looked far from a finished product when he hit .264 in 148 at-bats with the Brewers following the trade.

The Brewers have been terrible so far this season, and it's hard to imagine where they'd be without the surprise play of Segura. The 23-year-old has all the makings of a perennial All-Star, and he should have a stranglehold on the shortstop position for the foreseeable future in Milwaukee.