The biggest question about determining a catching prospect’s value is a simple one: Does he project to stay behind the plate as a major leaguer? If the answer is no, his value takes a significant hit. Determining that answer for players several levels below the majors, however, is not so simple.

One quantifiable way to measure an element of a catcher’s responsibilities is to examine his caught stealing percentages, and to compare it to the minor league average. Controlling the running game is only one part of a catcher’s defensive responsibilities, but blocking, receiving and game-calling ability are impossible to quantify. For that, we rely on managers, scouts and other educated people in baseball.

While there is a significant jump between Triple-A and major leagues in terms of caught-stealing percentages, there isn’t much of a difference or a trend between the other full-season levels of the minor leagues.

The entire list of every catcher in the minor leagues in 2007 would be extremely long to publish and, frankly, quite cumbersome to read. What follows is a list of every catching prospect who appeared in the 2007 Prospect Handbook and who had at least 40 stolen bases attempted against them in the minor leagues.

The ‘+/-’ column indicates how much better or worse a player was relative to the minor league average. The final column measures his combined average for every level he played at in 2007 (major leagues excluded), weighted by stolen base attempts against.

One caveat: Caught stealing percentages are not entirely a catcher’s responsibility. Pitchers also have a hand in holding runners on, and certain pitchers are slower to the plate. And in the minor leagues, in particular, pitchers are still learning the finer points of pitching. Some organizations even mandate that a pitcher not use the slide step before he reaches Double-A.

Again, these numbers are only one piece of a greater overall picture, one that requires the input of scouts and coaches to properly assess a catcher’s defensive abilities.

A look at a few interesting names on the list:

Kurt Suzuki: Suzuki took over for Jason Kendall when the A’s traded Kendall to the Cubs, and he has stepped in admirably. Suzuki is Kendall’s equal as an offensive player, and in terms of controlling the running game, the A’s don’t lose much with the cheaper Suzuki.

Geovany Soto: One can’t ignore Soto’s .353/.424/.652 line at Triple-A Iowa. And while those numbers are completely out of line with the rest of his career so far, he has always had excellent arm strength, and the numbers indicate he controls the running game well. Many catchers develop their offensive skills later in their careers than other positional players because of the high defensive demands placed on them, indicating Soto may be one to watch.

John Jaso: Jaso missed time in 2005 with rotator cuff problems, and he still wasn’t at 100 percent in 2006, when he threw out just 21 percent of basestealers despite having a plus arm. This year, Jaso threw out 35.2 percent of basestealers, 3.4 percent above the minor league average. At age 23, Jaso’s offensive line–.306/.408/.484 for Double-A Montgomery–is also intriguing.

Here are the top 10 catching prospects from our midseason prospect rankings, ranked by caught stealing percentage above the minor league average, with their midseason ranking in parentheses:

The negative percentages immediately stand out. Those figures should not come as a huge surprise, though, because no matter how good his defense is, a catcher still has to hit to play in the majors.

Jeff Clement: Clement can hit, but his ability to stay behind the plate has come under more scrutiny as he’s advanced. Some scouts felt that, despite his average arm, he didn’t set his feet well enough. This year, however, he controlled the running game relatively well. It’s unclear where Clement fits into the picture in the Mariners organization with Kenji Johjima in Seattle.

Taylor Teagarden: The Rangers drafted Teagarden in the third round in 2005, largely based on his superb defensive abilities. However, Teagarden missed most of the 2006 season recovering from Tommy John surgery and a disc problem in his back. The Texas product hit very well this season, but his caught-stealing sample size is smaller because he caught just 30 of his 81 games for high Class A Bakersfield, and 14 of 29 games for Double-A Frisco, spending most of his time at DH.

Hank Conger: Conger hit .290/.336/.472 as a 19-year-old for low Class A Cedar Rapids. He is lauded for his well above-average arm strength, but there were concerns before the season about whether he could stick at catcher because he is not light on his feet. In 99 attempts against, Conger threw out just 21% of basestealers, which is well below average and may be a cause for concern.

Matt McBride: Among all minor league catchers with at least 40 stolen base attempts against them, McBride ranked third-worst behind only high Class A Brevard County’s Angel Salome (-18.8 percent) and Double-A Montgomery’s Josh Arhart (-20.7 percent). At age 22, McBride was already old for the South Atlantic League, and his offensive output–.283/.348/.432–is not overwhelming, especially if he has to switch positions.

Finally, for those of you wondering who the top catchers in the minor leagues were, regardless of their prospect status, take a look at the top 10 from 2007: