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04/29/11 10:00 AM ET

It's all in the arm: Outfield guns potent weapons

Combination of strength, accuracy can save numerous runs

CLEVELAND -- Standing in the Indians' clubhouse before a game, Shin-Soo Choo reaches into his locker and pulls out a baseball. He takes the ball in his left hand, and in the blink of an eye, spins it, catches it and finds the top of the horseshoe seam with his index and middle fingers as he cocks back his arm.

This, Choo explains, is the four-seam grip that gives him one of the deadliest weapons in the Majors.

A converted pitcher who shifted to right field shortly after arriving in the United States from his native South Korea 10 years ago, Choo is in possession of that rare commodity -- a game-changing outfield arm.

"I can still hit 95 [mph]," Choo proudly proclaims.

The Twins would probably agree.

Last weekend, both Alexi Casilla and Justin Morneau tested Choo's arm -- in the same inning, and with the same grim result.

Casilla tried to score from second base on Jason Kubel's single to right, and Morneau tried to score from second on Michael Cuddyer's two-out single to right. Both ran through third-base coach Steve Liddle's stop sign, and both were thwarted at the plate by a bullet from Choo.

"Best thrower in the game," one American League scout said of Choo. "Better than Ichiro."

That's high praise, as, even at 37, Ichiro Suzuki's right arm is still highly regarded. It has been since the second week of his Major League career, when Terence Long, the A's speedy center fielder, tried to go from first to third on Ramon Hernandez's seemingly routine single to right field. Ichiro charged in on the ball, made a perfect strike to third to nab Long, and just like that, announced his arrival as an arm best left untested.

"Ichiro came up with a throw from right field that needs to be framed and hung on the wall at the Louvre next to the Mona Lisa," wrote John Hickey in the next day's Seattle Post-Intelligencer. "It was that much a thing of beauty."

Ichiro has some esteemed company on the list of all-time great outfield arms. Willie Mays made "The Catch," but his throws were always a threat. Jesse Barfield threw out 18.9 runners per 162 games in his 12-year career. Tris Speaker, Carl Furillo ("The Reading Rifle"), Dwight Evans, Al Kaline, Dave Parker, Mark Whiten, Raul Mondesi, Larry Walker and Vlad Guerrero were all, in their prime, the bane of baserunners.

But nobody had an arm quite like the one attached to Roberto Clemente's right side. "El Howitzer," as it was called, was responsible for gunning down 266 baserunners, by far the most by any player since World War II.

"Clemente could field the ball in New York," Hall of Fame broadcaster Vin Scully once said, "and throw out a guy in Pennsylvania."

Indeed, there is something both intimidating and inspiring about an outfielder who has such ability. When I was a kid growing up in Cleveland, the poster hanging on my bedroom wall was not of Cory Snyder belting one of his 149 career home runs, it was of Snyder, cornily dressed in a cowboy outfit, glove in one hand, ball in the other, and the word "GUNSMOKE" plastered across the top.

The elite arms capture our imagination that way.

But come to think of it, how many arms in the game today can truly be classified as "elite"?

It's a question capable of provoking a wide array of answers, depending upon your approach. Even if teams routinely put radar guns on their outfielders, which they don't, pure velocity readings would only tell part of the story (sorry, Choo). Same with outfield assists, which can either be a reflection of how effective a fielder is at throwing out baserunners or of how often baserunners feel they can test him.

Truth be known, there is no tried-and-true metric for measuring an outfielder's impact, though some have tried to concoct one. Fangraphs.com has a stat called, appropriately, ARM, which gives fielders a credit (plus or minus) depending on what runners do on a hit or fly ball. The runner can stay put, advance or be thrown out, so a fielder gets credit not only for throwing out advancing runners but for keeping runners from attempting to advance.

Looking at the 2010 and 2011 seasons, to date, the Royals' Jeff Francoeur ranks first, with a 9.8 ARM. The Blue Jays' Jose Bautista (7.1), the Mets' Angel Pagan (6.7), the Rangers' Josh Hamilton (6.5) and Choo (5.7) round out the top five.

If we take that ranking back a bit further, beginning with the 2007 season, Francoeur still leads the list, with a 33.8 mark, followed by the Phillies' Shane Victorino (20.3), the Nationals' Jayson Werth (17.5), the White Sox's Alex Rios (16.4), the Astros' Hunter Pence (15.9), the Cubs' Alfonso Soriano (15.2), the Rays' B.J. Upton (12.8) and the Orioles' Adam Jones (10.9).

But while the numbers can be a guide, defensive analysis is often best expressed by those who watch the game daily and have an educated take on what they're witnessing.

Scouts grade players on a scale from 2 to 8, with 2 being a "non-player" and 8 being "outstanding." One AL team compiled its scouts' reports and came up with seven players who ranked between 6.5 and 8: Choo; the Dodgers' Andre Ethier; the Rockies' Carlos Gonzalez; Jones; the Dodgers' Matt Kemp; the Pirates' Andrew McCutchen; and the D-backs' Justin Upton. The Orioles' Nick Markakis, Upton and Werth were in the 6 to 6.5 range.

One AL scout assigned to the National League East noted that the Marlins' Mike Stanton and the Braves' Jason Heyward both possess above-average arms, with Heyward having the edge on accuracy. An NL scout assigned to the West divisions listed the Rangers' Nelson Cruz among his picks. Another AL scout who focuses on the Central divisions mentioned the Brewers' Carlos Gomez as someone with a "big arm" but having accuracy issues.

Those are the professional takes. What do the fans think?

Well, Fangraphs also has a "Fans Scouting Report" section that takes those opinions into account. The Reds' Jay Bruce and Markakis led the "arm strength" ranking with 92 each, and Markakis, Bruce and Bautista were the only three outfielders to score in the 90s in "arm accuracy."

But although scout and fan acclaim has its place, the greatest compliments to an outfielder's arm come on the field, in the decisions made by the third-base coaches, who determine when and when not to send a runner.

"Since infield [practice] is a lost art, you have to watch film or even watch them play catch before the game," Royals third-base coach Eddie Rodriguez said. "I even watch the wind. You have to weigh a lot of factors. Overall, I know the guys who have an average to better arm. And with those guys, in a crucial situation, where you know you have to gamble, you just roll the dice."

Indians third-base coach Steve Smith explained it this way: Coaches are generally going to send guys with two outs and hold guys with no outs. The one-out play, he said, is the separator. If a coach is holding the runner on a one-out play, then that's a pretty good indication of his respect for the outfielder's ability.

"There's three things," Smith said. "A good arm, a quick release and accuracy. When you have all three, like Choo does, it's impressive."

And when you have all three, you can often come out on the winning end of what is, arguably, the game's most exciting moment: the close play at the plate.

But as Francoeur noted, natural ability isn't everything.

"I know I have a strong arm," Francoeur said, "but I do a good job of getting rid of the ball quick. That helps, too. I think it just comes from working on it. Our outfield coach will hit us 10 to 15 ground balls before the game, just working at staying down and coming up at full speed. We do it so much that you don't think about it [during a game]. You just see the ball and react."

The right grip helps, too. The scout who called Choo the "best thrower in the game" did so in part because of Choo's four-seam technique.

"Choo throws the ball on a straight line," the scout said, "with tremendous backspin that makes it carry further before it hits the ground, making him much more accurate. It's like a Jonathan Papelbon-type fastball. Pretty straight, but with explosive riding life at the end."

And with that life, that speed and that accuracy comes the ability to routinely gun down runners.

It's a game-changing talent that few possess.

"Sometimes," Choo said with a smile, "it feels better than hitting homers."

Anthony Castrovince is a reporter for MLB.com. Read his columns and his blog, CastroTurf, and follow him on Twitter at @Castrovince. This story was not subject to the approval of Major League Baseball or its clubs.