FORT MYERS -- The issue is not the unsettled shape of the Red Sox pitching staff. It is not what the Red Sox decided to do or not do this offseason, or the team’s willingness to sit on the sidelines of the sweepstakes for Yu Darvish or C.J. Wilson or Edwin Jackson or, to date, Roy Oswalt.

Those are all symptoms. In many respects, the bigger issue is the root cause that has loomed over the Red Sox in their roster building.

From 2005-09, the Red Sox experienced an incredible, franchise-transforming run of homegrown pitchers who came up and delivered dominance from almost the first moments of their big league career. Jonathan Papelbon became a fixture on the Red Sox staff in 2005; he was followed by Jon Lester in 2006, Clay Buchholz in 2007, Justin Masterson in 2008 and Daniel Bard in 2009. That’s five straight seasons in which the farm system yielded an impact pitcher.

But that steady harvest was interrupted in 2010 and 2011. Felix Doubront looked like he might represent the next in that line of pitching prospects for part of 2010, but he was injured down the stretch that season and likewise suffered through a halting 2011 in which he was unable to become a significant factor in the majors due to injuries. Kyle Weiland seemed ready to impact the big league club in 2011 after a dominant first half in Pawtucket, but he stumbled through his adjustment to the majors. Thus it has been the case that no one since Bard has emerged as a central member of the big league pitching staff.

The impact of the team’s shortage of homegrown arms has been at the heart of the questions at the back of the rotation. Had Doubront been ready to step into the big league rotation at some point last year, then perhaps the September collapse never would have happened, and perhaps the Sox wouldn’t be left to sift through a giant open competition for the final two spots in their rotation.

But there was no solution to be found inside the organization. And so, the Sox had to acquire a number of pitchers (mostly veterans on minor league free agent deals) from outside the organization this offseason.

That doesn’t rule out the possibility of a good rotation or pitching staff (witness what the Yankees got last year from Bartolo Colon and Freddy Garcia), but it does mean that the Sox will have to court greater uncertainty to get there than they would had their farm system continued its significant annual yields.

Teams like to build around young, talented, homegrown pitchers because they project to improve and they typically offer a greater likelihood of health and, hence, predictability. Veterans who sign minor league deals do so because they represent various risks, whether due to injuries or performance declines; as such, there is an element of a lottery ticket associated with their roles on pitching staffs.

Even so, in 2012, the Sox are an organization that features few homegrown pitchers whose minor league performances have them pounding on the doors to the majors. That notion was reinforced on Thursday, when the Sox released their full list of invitees to spring training.

There are 34 pitchers in big league camp, of whom just 10 (if one includes Daisuke Matsuzaka) are homegrown. Of the 15 pitchers who represent non-roster invitees to camp, just one -- Alex Wilson -- is a player who came up through the Red Sox system.

That non-roster group is interesting, since it’s a pool typically comprised of veterans who sign as minor league free agents and players who blitz through the minors after being drafted to pound on the door to the majors a season or two before they need to be added to the 40-man roster. With that latter group, their performance dictates their presence in camp.

This year, the Sox’ big league camp will feature some pitchers who have been brought up in the system such as Drake Britton and Stolmy Pimentel. But both of them finished 2011 in High-A Salem. Both are in big league camp not because they are expected to contribute to the major league roster this year but instead because the Sox wanted to ensure that another organization didn’t take a flier on them in the Rule 5 draft.

Britton and Pimentel both have big-time stuff but are in need of significant development before they reach the majors. If they hadn’t been added to the 40-man roster to protect them from the Rule 5 draft, they might not be in big league camp. Wilson is the only homegrown pitcher whose minor league performance has dictated that he will soon be in position to make his major league debut.

In noting the decrease in top-shelf Sox pitching prospects, there are meaningful caveats and considerations.

First, the Sox might well have next-in-line options at their disposal had they not traded a pair of them. The Sox drafted Casey Kelly in the first round in 2008 and used him as the centerpiece of the deal to acquire Adrian Gonzalez. Though Weiland was not the solution for the Red Sox last year, he would have been an important farm system depth option this year as either a starter or reliever had he not been traded to the Astros for Mark Melancon.

Secondly, there are still some homegrown players who are already on the 40-man roster with a chance to make an impact this year. Doubront remains on the 40-man roster, and the left-hander is out of options. He’ll be stretched out as a starter, but with the opportunity to compete for a job in the rotation or the bullpen. Michael Bowden (who is out of options) and Junichi Tazawa will be evaluated as potential relievers for the big league team. The Sox also have Wilson, who has developed to the point where the team feels strongly that he is close to making an impact.

The Sox do have some potentially significant pitching prospects on their horizon as well. Anthony Ranaudo, the 2010 sandwich pick, receives raves throughout the organization for his stuff and makeup. By next year, he is expected to be knocking on the door to the majors. Pimentel and Britton suffered down years in 2011, but if they can bounce back, then both could likewise put themselves in position to pitch in the majors by 2013. The Sox top pick in the 2011 draft, Matt Barnes, also is viewed as a future big league starter.

But those homegrown reinforcements likely will make their biggest impact in future years. In the short term, the Sox had to go the veteran free agent route in an effort to construct the sort of depth that they will need to withstand the typical attrition of the season -- a process that has continued right to the doorstep of big league camp with the signing of Ross Ohlendorf on Thursday. In that sense, the Sox are in a less enviable position than their divisional rivals.

The Yankees have 34 pitchers in big league camp, with 14 being non-roster invitees. Of those, 16 are homegrown players who were either drafted or signed as international amateur free agents; seven (exactly half) of the non-roster invitees are draftees.

The Rays have 30 pitchers in their spring training, of whom 13 have spent their entire careers with Tampa Bay -- 11 on the 40-man roster, and two more from their pool of seven non-roster invitees.

What the Rays in particular are accomplishing is somewhat remarkable. They are capable of filling out a rotation entirely with homegrown options (James Shields, David Price, Jeremy Hellickson, Wade Davis, Jeff Niemann) reinforcing it with more homegrown options (Matt Moore, Alex Cobb) and thus putting themselves in position to trade arms (Scott Kazmir, Matt Garza) as surplus inventory.

“It’s everything to us,” pitching coach Jim Hickey said late last season of his rotation, which led the AL last year in ERA (3.53) and innings (1,058) while getting all 162 starts from homegrown players. “Every organization would probably claim that their lifeblood is pitching, but that is ours -- young pitching to allow a guy like Matt Garza to leave, and to be really, really confident that Jeremy Hellickson is at least going to come close to reproducing what he gave us, and then to acquire the four or five top-flight minor league guys for him. It’s everything. Without it, we’d be an also-ran.”

In the end, Hickey suggested, the Rays would rather have great homegrown pitching than piles of money with which to buy free agent pitchers. It’s hard to fault his logic. After all, the entire Rays Opening Day rotation will make, at most, $17.6 million in 2012, or a bit more than the $15.25 million salary John Lackey will receive while spending 2012 on the disabled list for the Red Sox during his recovery from Tommy John surgery.

“If you start talking about gobs of money where you can pick and choose a piece here and there to buy to address a need, it’s pretty sexy,” Hickey said. “But I think any of these clubs, especially the clubs we’re competing with -- we’re competing with them all, but the Yankees and the Red Sox -- either one of those would swap their five for our five now. It’s interesting, because even with all the tens and hundreds of millions of dollars, the question mark on both those clubs [in September 2011] is starting pitching. It’s pretty tough to put a price on.”

That reality prompted the Yankees to trade for a young starter in Michael Pineda and to sign Hiroki Kuroda this offseason, even at a time when they have highly regarded prospects Manny Banuelos and Dellin Betances nearing the point of being major league ready.

The Sox, meanwhile, went with a number of buy-low options, and as such, their rotation will remain, in Hickey’s phraseology, “the question mark” on their team as they enter the year, something that general manager Ben Cherington acknowledged earlier this offseason. That reflects less on the team’s inability to find common ground with a pitcher like Oswalt than it does on the fruits of the farm system.

Of course, that assessment is drawn from a snapshot in time. Meanwhile, the shape of farm systems is dynamic and changes significantly over months or seasons. The assessment of the relative strength of homegrown pitching could shift meaningfully by the middle of the year.

If Betances and Banuelos struggle in Triple-A, or if some of the young Rays pitchers like Moore or Hellickson struggle, or if Sox pitchers such as Wilson or Ranaudo break through, then the view of the farm systems of the AL East could be very different by the middle of the season than it is now.

But for now, for this offseason, the Red Sox have been left trying to find creative solutions for the back of their rotation because their remarkable run of graduating pitching prospects to the majors has been on hiatus for the past two years.