FORT MYERS, Fla. -- The non-drama of the Red Sox pitching plans for Opening Day is now past. Jon Lester gets the first game of the year against the Tigers, while Josh Beckett gets the first Red Sox home start against the Rays on April 13.

That’s all well and good. So, too, is the curiosity about how Daniel Bard will fare in his likely conversion to the rotation and the unresolved matter of the Sox’ fifth starter.

But in many respects, all of those rotation spots represent secondary story lines. Meanwhile, the pitcher who represents perhaps the biggest factor in upgrading the Red Sox pitching staff from what it was a year ago remains almost unnoticed this spring.

The list of contributing factors to the Red Sox’ unraveling last year is lengthy. When a team misses the postseason by a single game, it’s easy to identify culpability from virtually every player on a roster. Yet a compelling case can be made that above all other elements, the stress fracture in Clay Buchholz’s back was the central cause of the Sox’ deterioration.

The impact of Buchholz’s absence was akin to the injury itself. Initially it appeared the Red Sox could persist through it, but the cumulative stress created by his loss ultimately made the issue acutely damaging to the point where it was debilitating.

It is easy to forget that Buchholz had been outstanding prior to -- and even through -- his back injury. After a poor April in which he was 1-3 with a 5.33 ERA, the Sox won eight of the right-hander’s next nine starts, with Buchholz going 5-0 with a 2.59 ERA while striking out 45 and walking just 15 in 55 2/3 innings.

He would mention the feeling of discomfort in his back during that stretch, but he was pitching so well that the issue was dismissed as relatively insignificant. But then, it was no longer insignificant.

The Sox went into the year hoping that 2011 would mark the season in which Buchholz emerged as a perennial 200-inning pitcher. Instead, his 14th start of the season became his last, as Buchholz logged just 82 2/3 innings.

“I can pitch with pain. It’s the unbearable stuff when you cringe whenever something happens. That’s how it was in Tampa [during the start on June 16]. I tried to do that for three innings. It was the worst pain I’ve ever felt anywhere in Tampa,” Buchholz said. “When it started, it felt like a muscle strain that needed to be stretched out and I could pitch with it. But this was a completely different feeling, something that I can’t pitch with.”

Through June 16, when Buchholz made his final start of the season, Red Sox starters owned a combined 32-17 record and 3.91 ERA. With three dominant starters at the top of their rotation and a merciless lineup, the Sox had overcome their poor start to blitz to a 41-27 record (.603) and a 1½ game lead in the AL East.

From that point forward, the starters as a whole were 32-33 with a 4.94 ERA while averaging 5 2/3 innings per start. Beckett and Lester, both of whom missed some time due to injury, posted solid numbers (a combined 13-12 record and 3.54 ERA while averaging roughly 6 1/3 innings per start) while Buchholz was out.

The rest of the rotation was abysmal in its 61 starts. The group went 19-20 with a 5.80 ERA while averaging just 5 1/3 innings per outing. Not coincidentally, the Sox went 49-45 (.521) in the post-Buchholz stretch of the year.

In September, his absence proved too much. Lester pitched poorly. Beckett missed one start, had a strong return against the Rays, then got hit hard in his final two starts of the year. Beyond those two, the Sox had no reliable third starter to step up.

John Lackey’s year-long struggles persisted. Erik Bedard, acquired at the trade deadline in an effort to solidify the Buchholz-free rotation, missed most of the month. Tim Wakefield was 1-5 with a 5.43 ERA in his last 10 starts, with the Sox going 3-7 in those contests. Kyle Weiland and Andrew Miller performed poorly.

There was no answer. For Buchholz, the seemingly endless rehab process at a time when his team was falling apart created a feeling of helplessness.

“That’s why I was so hard on myself trying to get back last year. I knew that if I was 95 percent, I could go out there and pitch to my 95 percent capabilities, I could help the team win half the time I was out there at least,” said Buchholz. “It was hard sitting on the bench, watching your teammates and friends go through struggles that they never really had to go through. It’s tough sitting there, having to watch it and not being able to help in any way.”

Buchholz is no stranger to disappointing ends to a season. In 2007, the Red Sox shut him down in September over concerns that his shoulder was fatiguing. In 2008, he was demoted. In 2010, he missed his final start as a precaution after experiencing lower back pain, something that cost him a shot at the ERA title.

But while none of those developments was easy to endure, all of those issues were blips. What happened in 2011, Buchholz said, was different, something that not only cost him more than half of the season but that also forced him to confront his pitching mortality.

“When I was rehabbing for two and a half months and it didn’t get better, I was the same as someone would be if they had an issue with their back, a crucial part to the sport they play or the job they do,” said Buchholz. “I felt that way. [But] after the first step, when I felt it getting better and was able to do certain things without it hurting, I knew I was going to get better and be alright for this year.”

Indeed, the fact that he appeared in some games in fall instructional league, was added to the big league roster for the final game of the season and then returned to the instructional league for one final outing offered reassurance to the pitcher. Still, he felt compelled to start throwing earlier than ever this offseason.

Buchholz typically starts throwing in mid-December. This offseason, he bumped up that timetable by about one month.

“I just wanted to make sure that if there were any setbacks, there was a little bit of offseason instead of throwing for the first time here, getting hurt, and having everyone look at me like, ‘Why didn’t you get better in the offseason?’ ” Buchholz said.

That approach suggested that contractual security did not create complacency in the pitcher. Buchholz and the Red Sox agreed to a four-year, $29.945 million deal in April that takes effect this season and runs through 2015, with team options for both 2016 and 2017.

Had Buchholz not signed that deal, his injury would have proved a costly proposition. His earnings through salary arbitration would have taken an unquestionable hit.

Because he signed his long-term deal, Buchholz did not have to worry about the financial implications of his injury. It became easier for him to understand the importance of addressing his health for the long haul.

Even so, while it was significant for Buchholz to have financial security, it did not dampen the disappointment of being unable to pitch.

“That was something I would have beat myself over if I hadn’t signed a contract, had this last year and got hurt and wasn’t able to pitch,” said Buchholz. “That would have been hard for me, because I would have definitely pushed myself to get back a lot sooner and maybe hurt myself worse. That helped out a little bit.

“All my friends told me in the offseason, ‘Hey, at least you signed a contract,’” said Buchholz. “But it’s like if you’re on a losing team and people say, ‘At least you get to lose in the big leagues.’ Losing gets old, regardless of how much money you’re making.”

Buchholz is likewise not thinking about money this spring. He’s thinking about doing something he’s never done before, chiefly, making it through 30-plus starts in the big leagues. (It is worth noting, however, that Buchholz did make 34 starts in 2009 between the majors and minors, logging a career-high total of 196 innings.)

As he focuses on that pursuit, this spring has been one of rediscovery for Buchholz. The experience of pain-free pitching has offered a degree of novelty for the right-hander.

“I sort of forgot what it felt like there for a while,” he noted.

A healthy Buchholz is a game-changer for the Red Sox. If he, Lester and Beckett can ever be healthy in the same season, the Red Sox could feature a front three capable of competing with any in the American League.

After all, Buchholz has a 2.70 ERA since the start of 2010, in a virtual tie with Jered Weaver for first in the American League and third in the majors (behind only the last two NL Cy Young winners, Roy Halladay and Clayton Kershaw) during that span (min. 250 innings).

The Red Sox have been in virtually game Buchholz has started in the last two years, as he’s allowed five or fewer earned runs in each of his last 42 starts. The last Sox pitcher to go on such a run? That would be Roger Clemens, who did it between 1985-87.

The right-hander features an arsenal that is as good as any on the Red Sox, with a repertoire that allows him to attack both sides of the plate against both right-handers and left-handers, something that helps to explain his similar numbers last year against both right-handed hitters (.242 average, .314 OBP, .392 slugging, .706 OPS) and left-handers (.241/.305/.401/.706).

When healthy, Buchholz features a mid-90s four-seam fastball, a nasty two-seamer that has become a groundball-inducing machine, a cutter that saws off left-handers and the swing-and-miss curveball and changeup that long ago made him one of the most highly touted prospects in baseball.

Buchholz is now long past his prospect status. He’s now 27, and in what should be the prime of his career.

That status was undermined in 2011 by an unexpected injury, but to date this spring, Buchholz has yet to consider the back a cause for any concern. He’s been sharp all spring, allowing three runs in 10 innings (2.70 ERA) while striking out seven and walking two.

It is a promising beginning to what Buchholz hopes will be a more satisfying end to a season than he has ever experienced. Though he will not get the most prestigious starts of April, his outings will be no less important to the Sox than those made by Lester or Beckett.

To the contrary, a strong case can be made that Buchholz is the pivotal member of the 2012 Red Sox rotation. It is a responsibility for which the right-hander is eager.

“I’ve been ready to go for about six months now. It’s been a while,” Buchholz said. “I feel like this is where I belong. It’s what I want to do.”