FORT MYERS, Fla. -- The description was unusual.

Near the start of spring training, Bobby Valentine was asked for a description of the defense of Kevin Youkilis in 2011. In response, Valentine described the number of plays that the third baseman had made, relative to the league average, on balls hit to his right, left and in front of him.

In other words, he was evaluating defense through the same system described in “The Fielding Bible,” the annual tome put out by John Dewan and Ben Jelovec of Baseball Info Solutions.

Dewan has become one of the pioneers in the field of defensive metrics both for having developed a system that accomplished two things.

First, he identified a system that can measure defense relative to a league average. A staff of Baseball Info Solutions folks watch every play of every major league game at least three times to chart every ball in play, looking for its location, the velocity off the bat of every ground ball and the hang time and arc of every fly ball.

Secondly, Dewan made defensive metrics accessible by phrasing them in simple-to-digest terms: How many defensive plays above or below average at his position does a player make? How many runs did he save or cost his team.

Dewan dropped by JetBlue Park on Monday, and between what he said in the visit and the content of Volume III of “The Fielding Bible,” an interesting portrait of the Red Sox defense emerged. Here is a position-by-position look at the Red Sox’ defense:

CATCHER: JARROD SALTALAMACCHIA / KELLY SHOPPACH

Saltalamacchia graded as a below-average defensive catcher in 2011, costing the Sox four runs as compared to the average catcher. However, The Fielding Bible noted that he’s on an upward trajectory as his experience increases, and suggests that he “has the athleticism to find success behind the plate.”

Interestingly, Dewan described Jason Varitek as an above average catcher for his handling of the pitching staff and ability to block the ball (thus preventing wild pitches and passed balls), traits that more than made up for his inability to control opposing running games.

As for Shoppach, desite his limited playing time in Tampa Bay last year, Shoppach’s outstanding caught stealing numbers (37 percent), blocking and receiving abilities resulted in his saving three runs over the average catcher, a number that ranked among the top 10 catchers in the majors.

FIRST BASE: ADRIAN GONZALEZ

Gonzalez won the Gold Glove last year, and the Fielding Bible seconded his worthiness for the award. It is not just physical skill but also acumen that earned him such praise.

“He possesses a combination of soft hands and sensible, quick judgment that few in baseball can match,” the book suggests.

Gonzalez was credited with saving 12 runs in 2011, doubling his average of six runs saved per season in 2009-10.

SECOND BASE: DUSTIN PEDROIA

No secret, Pedroia is one of the best in the game. He won his second Gold Glove in 2011, and was also named the best defensive second baseman in the game by Dewan and a panel of his peers, getting credit for 18 runs saved.

Dewan said that the standouts at the position in 2011 were Pedroia, Ian Kinsler and Ben Zobrist.

At times, there has been a debate about whether Yankees second baseman Robinson Cano has been Pedroia’s equal. For Dewan, that is no question at all.

“When you watch Robinson Cano turn double plays, he's the best. There's no question. Sure enough, we tabulate good fielding plays on double plays and he has more than anybody in baseball,” said Dewan. “But you know what? He has more misplays than anyone in baseball. And based on our calculations, those misplays cancel out his good plays. He's so fast on that ball, that he'll make a play. But a lot of times, that very transfer that he's doing so quick, he'll make an out on the double play, or he'll out and out make an error.”

Cano was credited with having saved one more run than the average second baseman in 2011.

SHORTSTOP: MIKE AVILES

In 2008, Aviles graded as an excellent infielder, having saved 12 runs above the average defender while shifting between shortstop (his primary position), second and third. After that, however, Aviles graded poorly, costing his team eight defensive runs in 2010 and two in 2011.

Per the book: “His footwork isn’t very good regardless of position, but his range is adequate, and he does have the arm strength necessary to make all the throws from third base or shortstop. However, Aviles is a tentative defender even on routine plays, and he made a lot of defensive miscues, both of the mental and physical variety. He did not appear to take well to the role of a utility man. Overall, his net -11 Good Fielding Play minus Defensive Misplays and Errors was worse than all but eight infielders in the league, regardless of position. If Aviles ever hopes to be looked upon as more than a backup infielder, his glove work needs to improve.”

It is worth noting that Dewan’s assessment of Aviles’ defense was based on his work at third base. Assuming he is the everyday shortstop, Aviles would either need an even more drastic improvement from last year or, if he continues to measure significantly below average, he would need to hit like crazy to offset his shortcomings.

A caveat: One Red Sox team source suggests that the club’s internal metrics (developed by are somewhat more bullish on Aviles than Dewan’s projection system, particularly given his steadily improving arm strength in the post-Tommy John stage of his career.

The Sox also expect to have Nick Punto to split time with Aviles at shortstop. Dewan described Punto thusly: “The Red Sox have a guy, Nick Punto, who’s very good at third, very good at second, average at short. That’s just generally what you have. If you have a guy who’s a little below average at short, he’s generally above average at second and third.”

Curious how Jose Iglesias rates? He doesn’t.

“Right now, we do some scouting for some of the minors, but nothing we provide to the public right now,” said Dewan. “We have some confidential clients. Regarding Iglesias, we don’t know where he’s going to come in.”

One more footnote in the exercise: Dewan pegged Marco Scutaro as being one run better than league average in both 2010 and 2011 at shortstop. “He remains a solid middle infielder, but at this point in his career he probably will never regain the defensive prowess he displayed across the Canadian border,” said the book.

THIRD BASEMAN: KEVIN YOUKILIS

Kevin Youkilis spent most of last year dealing with one ailment or another, which made it more difficult for him to move around at his position. Given those limitations, it is interesting to note how he fared overall last year, according to Dewan.

“Right on the button, zero,” said Dewan, taking stock of the fact that Youkilis neither allowed nor prevented more runs than an average third baseman. “Zero is average.”

Youkilis has a strong and accurate arm, allowing him to make eight more plays to his right than the average third baseman would have converted. According to the book, he struggled on balls on which he had to come in, on which he ranked as a -7.

The fact that Youkilis graded at average at the position would appear to bode well for what he might be able to do in the field this year now that he is healthy and able to move without restriction.

“I feel a lot more comfortable. I’m just excited to play baseball again, be able to go out there and feel good, run around,” said Youkilis. “When you feel like crap and you’re out there, it’s miserable. The game is fun. It’s supposed to be fun. Being able to go out there and actually do stuff, it helps a lot.”

LEFT FIELD: CARL CRAWFORD

Dewan spent some time marveling at the remarkable defensive season turned in by Yankees left fielder Brett Gardner.

“Left field, which is not normally a tremendous defensive position, Brett Gardner saved 23 (runs),” said Dewan. “That’s Crawford’s old numbers.”

But Crawford’s comprehensive struggles in 2011 extended to his defense. The left fielder, who perennially saved 10-20 runs per year while with the Rays (according to Dewan), was graded as two runs below average in 2011.

The natural inclination would be to say that the outfielder struggled to adapt to his new environment, particularly the challenging dimensions of Fenway. But that would offer a somewhat misleading picture, since Dewan clarified that Crawford was one run below average last year both at home and on the road, after having been plus-11 at home in the previous two years and plus-15 on the road.

Simply put, Crawford had a bad year. Red Sox officials concurred with such an assessment, believing that Crawford’s diminished confidence showed up on defense and at the plate. Dewan said that he would forecast a rebound by the left fielder to be an above average left fielder next year, perhaps someone who could save five runs.

Still, that is short of the remarkable standard he set with the Rays, the one that helped convince the Sox to invest in him to the tune of a seven-year, $142 million contract after the 2010 season.

It’s also worth noting that defensive aging patters typically feature a steady decline almost from the first time that players step onto a baseball field. That led Dewan to conclude in the book, “Now into his thirties and limited by a short left field, it’s likely his best defensive seasons are behind him.”

CENTER FIELD: JACOBY ELLSBURY

Ellsbury, in some ways, served as the vehicle for the introduction of newfangled defensive metrics to Red Sox fans after the 2009 season, when both UZR and the runs saved system crushed him, ranking him as one of the worst defensive outfielders in the game.

Last year, Ellsbury lived up to his job description as the quarterback of the outfield. He won a Gold Glove and while Dewan was a bit more guarded about his work (“He’s no Austin Jackson,” Dewan noted, referring to the Tigers center fielder who saved 29 runs) was rated as being seven runs better than the average outfielder.

Ellsbury received high marks for his range but was dinged for his struggles playing balls off the Wall and his throwing arm.

“I rate him slightly above average overall for a center fielder,” said Dewan. “We project he'll save two or three runs this year.”

RIGHT FIELD: CODY ROSS / RYAN SWEENEY

In Monday’s exhibition game, Ross made an impressive catch as he ran back onto the warning track in left field, hauling in a ball over his head as he twisted in front of the JetBlue Monster scoreboard. It was the second nice over-the-shoulder catch that Ross made in the span of a few days, but Dewan’s research suggested that such plays are far from the norm.

From "The Fielding Bible": “Ross has struggled with the difficult, high outfield walls in his home parks throughout his career. In Florida he had to deal with the ‘Team Monster’ in left field, and in San Francisco he had to handle the 24-foot chain-link fencing. His 15 defensive misplays over the past three seasons for ‘failing to anticipate the wall’ ranks second in all of baseball. Ross signed with the Red Sox in the offseason and is expected to see time in left field, where he will have to deal with his ultimate nightmare: the Green Monster.”

Of course, when Crawford is healthy, the primary defensive position for Ross will be right field, so perhaps the suggestion of a “nightmare” scenario will prove exaggerated. 

Sweeney had too small a sample size at all three outfield spots last year to get a good read on his abilities, but he has consistently posted statistics that were anywhere from average to well above-average no matter where he’s been stationed. He’s been at his best in right field, where Sweeney has been particularly strong at tracking down deep fly balls -- something at which J.D. Drew excelled, much to the benefit of the Sox pitching staff for years.

POSTSCRIPT: SO ARE THEY GOOD OR NOT?

In 2011, a year in which the Red Sox had three Gold Glovers (Gonzalez at first, Pedroia at second, Ellsbury in center), the Sox ended up being 17 runs better than league average, according to Dewan. For the coming year, Dewan projects that the Sox will still field an above average defense, saving 12 runs above average based on the career norms of the anticipated group of defenders.

There’s room for variation, of course. If Iglesias ends up playing shortstop for part of this year, one would expect the Sox’ run prevention to increase. If the Sox’ work on defensive fundamentals ends up, for instance, improving a pitching staff that was a defensive horror show last year, the Sox could enjoy a bigger boost.

Still, the projection of 12 runs saved is solid, ranking as the 10th best forecasted mark in the majors. However, it is a worse projection than Dewan forecasts for most of the anticipated power houses of the American League. The Rays (+42 runs, first), Rangers (+26 runs, fourth), Angels (+22 runs, fifth) and Yankees (+20 runs, seventh) all project to have better defenses than the Sox.

It’s an interesting exercise, but not necessarily a truly meaningful one. Most defensive systems acknowledge that the ability to project defense – particularly team defense, where it’s so difficult to predict the impact of how injuries and aging will change groupings over the course of the year – is limited.

“They do a good job telling me what happened,” Valentine said of advanced defensive metrics. “I don’t know what’s going to happen.”

Even so, baseball is getting closer to the point of being able to figure that out based on what has happened, with front offices engaged in their own version of a space race to figure out how to develop useful systems of prognostication. That, in turn, underscores the importance of the information in something like “The Fielding Bible,” which offers a window into that field.