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02/02/10 10:00 AM EST

Who will go from invitee to indispensable?

Players on the bubble can make a splash in spring camp

NRI isn't a new hit investigative TV series, and it isn't a political action committee.

But when the crunch-time roster-selection period known as Spring Training hits Arizona and Florida in a few weeks, it's one of baseball's most operative terms. It stands for "Non-Roster Invitee," and it signifies the players who go to big league camp under Minor League contracts in an all-out effort to make an impression and make the Opening Day 25-man roster.

Usually, it doesn't happen. Usually, NRI might as well stand for "Not Really Important," because many of these players, particularly veterans, will end up in Triple-A and, quite possibly, on waivers. Or perhaps they'll surface later on as they sign Minor League deals with other clubs and try the process all over again the following spring.

But you never know what will happen in baseball, and sometimes "Not Really Important" can quickly turn into "Now Rendered Indispensable." NRI guys have turned into 162-game stalwarts, and even October heroes.

Take Scott Spiezio, who showed up in the Cardinals' camp in 2006 as an NRI, made the team, then hit .272 with 13 home runs and 52 RBIs in 276 at-bats. He contributed to the club's World Series run with huge hits down the stretch and five RBIs against the Mets in the National League Championship Series.

And what about Mike Sweeney? The veteran first baseman and designated hitter who has been so hobbled with back injuries that he had to take a Minor League deal with Seattle just to stay in the game last year made the club, and, along with Ken Griffey Jr., was credited as being the driving force in turning around a clubhouse. The happy team went from an American League-high 101 losses to an 85-77 record in 2009, the best improvement in ball.

So who will strike NRI gold in 2010?

It's a good bet that D.J. Carrasco (Pirates), Josh Fogg (Mets), Brian Shouse (Red Sox), Eddie Guardado and Miguel Batista (Nationals), Jim Edmonds (Brewers), Derrick Turnbow (Marlins) and Scott Proctor (Braves) will surface on big league rosters before long. Carrasco, for example, is slated to make a base salary of $950,000 if he breaks camp with the Bucs as expected.

But other NRI success stories would be big surprises, and here is a handful to watch for 2010.

Dallas McPherson, 3B/1B, A's: True, Oakland swung a deal for Kevin Kouzmanoff to play third base, and true, the team still has the veteran Eric Chavez on the roster. But injuries happen, and who would know about that more than McPherson? The former Minor League Player of the Year was the Angels' can't-miss prospect before back problems ruined his 2007 and 2009 seasons, but when he's healthy, he can mash. He has a career Triple-A line of .280 average, .360 on-base percentage and .635 slugging percentage, and he could give the A's a nice power option at the hot corner -- or maybe even at first if Daric Barton doesn't work out.

Gustavo Chacin, LHP, Astros: In 2005, while with the Blue Jays, Chacin finished fifth in AL Rookie of the Year voting after going 13-9 with a 3.72 ERA in 203 innings at the age of 24. He wore glasses on the mound. He had style. Injuries and eventual shoulder surgery in 2007 slowed him down, but he re-emerged in the Phillies organization in 2009 and was healthy enough to pitch 115 1/3 respectable innings, carving out a 3.20 ERA in 19 starts.

Tony Pena Jr., RHP, Giants: Pena, a former Royals shortstop, became a full-time pitcher last year after hitting .098 in 2009 in 51 big-league at-bats. Then he went out, flashed three pitches -- including a 90-plus-mph fastball -- and put up a .176 batting-average-against in three Minor League stops. It could be he's found his calling as a late bloomer -- he turns 29 in March -- and it's happened before. Troy Percival, for example, came up as a weak-hitting catcher before making the switch to pitching and becoming an All-Star closer.

Ryan Shealy, 1B/DH, Rays: Shealy has been on Major League rosters since breaking into the bigs with the Rockies in 2005, but he's never gotten more than 202 at-bats in a season. And though last year, at the age of 28, he put up an incredibly small sample size of 73 at-bats, he hit seven homers and put up a line of .301/.354/.602 that should at least earn him a decent shot of backing up Carlos Pena and seeing what progresses after that.

Kameron Loe, RHP, Brewers: The last time we saw this 6-foot-8 pitcher, he was cutting his teeth in the Rangers organization, going 19-23 with a 4.77 ERA in 47 starts and 60 relief appearances and filling every role from starter to middle reliever to late-inning mop-up man. He pitched in Japan in 2009, then in the Mexican Winter League, where he had a 3.20 ERA in five starts and one relief stint. He has a sinking fastball that should reach the 93-94-mph range, and he also throws a slider, a curveball and changeup.

Doug Miller is a national writer for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.