In one respect, it should come as little surprise that the fate of Jason Varitek has consumed all the oxygen of conversations about the Red Sox. The man who has served as captain of the Red Sox since signing his last contract in 2004 has long been described as the backbone of a club that has won two World Series.

All the same, in a way, it’s almost surprising that his decision about whether to accept the Red Sox’ offer—undoubtedly the best one he will receive—is of such great consequence. The development represents a rare blemish on an area that has been one of the foremost team strengths in the past couple seasons.

Over the past few years, an assembly line of prospects has stopped numerous leaks almost as soon as they have emerged. Jonathan Papelbon…Dustin Pedroia…Jacoby Ellsbury…Clay Buchholz…Justin Masterson…Jed Lowrie…Jon Lester…

The list of contributing players drafted since the current ownership group took control of the Sox in 2002—and particularly under the auspices of G.M. Theo Epstein and scouting director Jason McLeod—is long and continues to grow. The Sox have hit on athletic outfielders, an MVP second baseman in Pedroia and a shortstop or super-utility player in Jed Lowrie, as well as pitcher after pitcher.

That development is a central part of the team’s blueprint for success. The Sox aspire to feature both an above-average regular (meaning one of the 15 most productive starters in baseball) at every position as well as enough depth at every position to be able to endure an injury to any one player without derailing.

“We’re trying to build a team almost like you would a football team,” said Vice President of Player Personnel Ben Cherington. “A college football team has a guy ready in waiting to take over once the primary guy, the starter or the primary guy, is no longer there for whatever reason. That’s what we’re trying to do. We’re trying to build that depth at every position.”

For the most part, the team has fulfilled that goal. But at the one position that is now magnified by the Varitek melodrama, the results have been less impressive.

By their own admission, the Sox do not have a ready-made replacement behind the plate should Varitek depart. Even after a season in which the 36-year-old hit a dismal .220 with a .672 OPS—both career lows—the Sox do not pretend that they have someone in their system who can take over for him.

“I think we would be in a better position if we had an obvious candidate to step right in…We do have some catchers who we feel are ready to start competing for big-league playing time: Dusty Brown, (George) Kottaras, Mark Wagner will be in big-league camp,” said Cherington. “I’d say it’s accurate that those guys haven’t proven yet that they’re obvious candidates to take over the position. They may yet, in time.”

For now, however, the Sox are forced to search for an answer elsewhere. They are hardly alone in the undertaking, a fact that reflects the unique challenges and high standards for the position.

Catchers are an extremely difficult lot to scout. In some respects, the amount of scrutiny that players must undergo to be drafted for duty behind the plate exceeds that of other positions, in part because it is a more challenging position to translate from the amateur to pro environment.

Playing outfield at the major-league and college levels is a fundamentally similar undertaking. The same is true of infield and, to a degree, even pitching. But catching becomes a different sort of animal altogether, requiring scouts to operate heavily on projection.

“It is,” McLeod notes, “a tough position to scout.”

While the physical tools—both offensive and defensive—of catchers are typically apparent at the amateur level, it is difficult to determine how a catcher will take to calling his own game, rather than having it called from the bench. A player’s ability to lead a pitching staff is often little more than guesswork.

So, too, is his ability to endure the punishing workload of time behind the plate on a daily basis. Some catchers simply don’t adapt well to the draining prospect of going from a three game a week schedule as an amateur to five or even six games a week of assuming the position as a pro.

“People want the great defender, someone who can handle the staff, someone who’s durable, someone who’s tough, someone who’s a leader, and oh by the way, you need to hit, too, and be part of an effective lineup,” said Cherington. “If you have one of those guys—there are probably two or three in baseball—then surely it’s an advantage.”

For that reason, those players who seem to combine the ability to manage a pitching staff while also sustaining their offensive productivity often get snapped up in the draft. Joe Mauer of the Twins, considered perhaps the best overall catcher in the game, was the No. 1 pick in the 2001 draft. In 2008, three of the first 10 draft picks (Buster Posey, Kyle Skipworth, Jason Castro) were catchers. Orioles catcher Matt Wieters, considered the best prospect in baseball, was taken with the fifth overall pick in the draft.

The Sox, by virtue of their perennial success, do not get their pick of the litter when it comes to catchers. Instead, drafting towards the bottom of the first round in most years, they typically find that the players at other positions are more compelling than a picked-over catching crop.

The team would not think about passing on the best available prospect just because of an organizational shortage of top catching prospects.

“It never gets to a point, certainly with our top picks, that we’re moving catchers up higher on the (draft) board because of need,” said Cherington. “But it is a priority to identify who we feel are the best catchers or perhaps the most undervalued catchers, and also identify guys who might be conversion candidates.”

The Sox believe they have some catchers in their system who have big-league potential, and who could even begin contributing soon. Brown (35th round, 2000) and Kottaras (acquired in a trade for David Wells in ’06) will both compete for a backup role with the Sox this year after the two combined for a productive platoon at Triple-A Pawtucket last year.

Some of the catchers taken by McLeod—including Wagner (9th round, 2005), Luis Exposito (31st round, 2005) and Tim Federowicz (7th round, 2008)—have the potential to contribute at the major leagues. But of those players, none is ready to displace Varitek and step in as the starting catcher for the Sox in 2009.

And so, the Sox retain a vaguely unsettled state as they await word about whether Varitek will return, wonder what kind of contribution he might make if he does, and continue to explore the trade market in hopes of identifying a catcher-of-the-future who must also contribute in the present.

For a scouting department that has been such a central part of the Red Sox’ success, the fact that the team is in such a position is something of a disappointment.

“It’s hard not to think, ‘Gosh, why can’t we get that catcher?’” conceded McLeod. “It’s definitely a position we’re trying to fill with an impact-type guy. We just haven’t hit it so far.”

Alex Speier is a senior writer for WEEI.com.