MLB.com Columnist

Phil Rogers

#ASGWorthy: Unsung studs prove their value

Mariners outfielder Martin leads group of players making breakthroughs

#ASGWorthy: Unsung studs prove their value

Young talent was a central theme of last year's All-Star Game, with a record 20 players who were 25 or younger suiting up at Great American Ball Park. There's a lot more of that in the pipeline for this summer's game at Petco Park, but the prodigies are under attack from a group of unsung candidates.

These guys weren't first-round Draft picks. Most of them didn't receive million-dollar signing bonuses, and the ones that did struggled to justify expectations.

Cast your Esurance All-Star ballot for #ASGWorthy players

Their success wasn't immediate, with many having to change positions or move to a second team -- or in the case of John Jaso, move to a fourth team and change positions -- to have their breakthrough season. But they deserve serious consideration as you cast your votes for the 2016 All-Star Game presented by MasterCard on July 12 in San Diego.

Leonys Martin is the headliner of the group.

The Cuban center fielder has been a big reason that the Mariners are leading the American League West. At age 28, he's contributing defensively (four Defensive Runs Saved, according to Baseball Reference) and he's playing with the combination of speed and power that the Rangers envisioned when they invested $5 million to sign him in 2011.

Martin stole 36 bases for Texas in 2013, but he never hit more than eight homers in his three seasons as a regular there. Seattle grabbed him in a deal built around setup man Tom Wilhelmsen, and Martin was hitting .262 with nine homers, 20 RBIs and eight stolen bases before he went on the disabled list Friday. His .822 OPS is 156 points higher than his career total with the Rangers.

Martin, who left Wednesday's game with a strained hamstring, delivered a walk-off homer Tuesday that provided one of the best moments for the first-place Mariners. He was building a strong case for himself, along with the Red Sox's Jackie Bradley Jr. -- who probably made himself a default choice with his hitting streak -- and Blue Jays center fielder Kevin Pillar.

Bradley Jr.'s 29-game hit streak

So are these other unsung All-Star candidates, by position:

Catcher: Francisco Cervelli, Pirates

A No. 2 catcher for most of his career, the 30-year-old Cervelli stepped into a regular job last year, and he played so well he just received a three-year, $31 million extension. He combines on-base skills as a hitter with pitch-framing excellence behind the plate, and like Jaso, he is playing for one of baseball's most open-minded organizations. Would any other team hit a guy fifth who was homerless through the first quarter of the season? The D-backs' Welington Castillo, who was traded twice last season, is a solid defensive catcher who hits with power. He's slowed down since his torrid start, but he could also still play his way to San Diego.

First base: Jaso, Pirates

Long a good on-base guy, the seventh-year Major Leaguer has emerged since growing flowing dreads and moving from catcher to first base. He's been an igniter for Clint Hurdle's team. Brewers first baseman Chris Carter, who is battling for the league lead in home runs, should also get a lot of votes.

Second base: Jean Segura, D-backs

An All-Star as a 23-year-old for the Brewers, Segura was deemed expendable after back-to-back down seasons. He's rediscovered his batting stroke after being traded to Arizona and moving from shortstop to second base, where his range is a major asset (five DRS). Miami's Derek Dietrich is a good offensive player whose value has been enhanced since he took over as a regular second baseman after Dee Gordon's suspension.

Segura's diving stop

Shortstop: Zack Cozart, Reds

Not that long ago, his calling card was his fielding (19 DRS in 2014, second to Andrelton Simmons among shortstops), but the 30-year-old Cozart emerged as a productive hitter while playing through injuries last season and has continued to hit this year. He could be an attractive trade option in July. The Brewers' Jonathan Villar is doing a lot to show he's more than a place-holder for prospect Orlando Arcia.

Third base: Travis Shaw, Red Sox

Like Mookie Betts and Bradley, Shaw is a success story from the 2011 Draft, which was the last one overseen by Theo Epstein in Boston. He was a ninth-round pick from Kent State and climbed through the minors slowly. He was ready when he got the chance to play first base last season and moved smoothly to the other corner this spring, outplaying Pablo Sandoval to win a job. The Marlins' Martin Prado was an All-Star second baseman/utility man for the Braves in 2010 and received Most Valuable Player Award votes for Atlanta in '12. He and teammate Marcell Ozuna are among the National League's leading hitters.

Shaw's two-run double

Left field: Adam Duvall, Reds

An 11th-round pick of the Giants in 2010, Duvall had two 30-homer seasons in the Minor Leagues, but he struggled when he got his first Major League chance. He was traded to Cincinnati for Mike Leake last season and he's taking advantage of a shot with the rebuilding Reds. The Rays' Brandon Guyer emerged as a solid regular in left field before shifting to center field after Kevin Kiermaier broke two bones in his left hand trying to make a catch.

Right field: Adam Eaton, White Sox

Driven to outplay his status as a 19th-round Draft pick, Eaton compiled a .348 batting average and .448 on-base percentage in his Minor League career. The D-backs dealt him to the White Sox. He hit .300 as a center fielder in 2014, but he has been even more of a factor after moving to right this season. Eaton is among the leaders in Wins Above Replacement, right there with Jose Altuve, Mike Trout and Manny Machado. Tampa Bay's Steven Souza Jr. struggled last season to fulfill expectations that followed him after the Rays acquired him from Washington in a three-team trade, but he is delivering this year.

Eaton's solo shot

Phil Rogers is a columnist for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.