In March, Pawtucket pitching coach Rich Sauveur was getting buzzed by a small hovercraft in the Red Sox' spring training clubhouse. His response was unexpected.

Sauveur saw that the toy was being steered by pitcher Clay Buchholz, with whom he had worked in Pawtucket in 2008 and 2009. And he took stock of the fact that the pitcher's playful clubhouse demeanor belied who he had become, on and off the mound.

"It wasn’t about stuff with him. It was about the mental part, the maturity," suggested Sauveur. "I’m amazed by him, how much he’s grown and matured. Instead of walking out the back of the clubhouse with a nine-iron or something, he’s walking out with his wife and baby. ... He’s matured so well."

Such reflections have become common in a Red Sox organization that drafted Buchholz out of Angelina Junior College in 2005 and then watched his unsteady progress through the professional ranks. And those sentiments helped to explain why Buchholz was sitting next to Sox GM Theo Epstein on Sunday afternoon to discuss a four-year, $29.945 million extension that could keep Buchholz under contract with the Sox through the 2017 season.

There was a time when that sort of deal seemed unfathomable. Buchholz was wildly talented, but he had not yet fully grasped what it meant to be a big league starting pitcher on a five-day routine, and what was necessary to sustain his health over the course of a full season and indeed for years to come.

Success, in some respects, came too quickly. He breezed through the minors because no one could do anything with his incredible ensemble of pitches -- most notably his exceptional changeup and curveball, which complemented a low-90s fastball. Then, of course, he burst onto the scene with his no-hitter in his second big league start in 2007, an apparent harbinger to greatness.

But that early success also came with a warning. Buchholz (who is 0-2 with a 7.20 ERA this year, following his dazzling 17-7, 2.33 campaign a year ago) was shut down for the duration of the 2007 season in late-September, left off the playoff roster even though his electric stuff would have represented an asset, because of weakness in his shoulder that left him at risk, the Sox believed, for an injury.

"I don’t think Clay would argue with me if I said that his first year, he wasn’t the most compliant guy with our shoulder program," Epstein joked on Sunday.

Meanwhile, off the field, his name started floating in the TMZ ether. When he followed his attention-grabbing emergence onto the big league scene in 2007 with a dire year-long struggle in 2008 (a season in which he went 2-9 with a 6.75 ERA), it was natural to ask questions about whether the pitcher's makeup would position him for success, let alone a long-term commitment.

But the Sox stuck with the young right-hander. They did not trade him when his value was lowest. And their patience was rewarded.

Buchholz embraced the responsibility of being a big league pitcher, committing himself to the between-starts regimen that would allow him to remain healthy for the long haul. And he also became more grounded in his life off the field, a notion that was underscored by the presence of his wife and baby girl at the press conference to announce the press conference.

It seemed no coincidence that Buchholz' on-field success in 2009 and 2010 coincided with those developments in his career and life, and it is certainly no coincidence that the Sox were willing to commit to him on a long-term deal upon seeing his maturation as a person and player.

"Clay has certainly earned our trust. He’s developed a tremendous amount as a player and as a person, from the time that he signed here out of junior college," said Epstein. "Now he’s a star pupil on the shoulder program. He gets his work in every day. He’s really settled in with his family life and on the field. He’s really become a trusted guy in this organization. ... We really trust him going forward. There are no guarantees in this game, but you want to be on the right people."

Meanwhile, the fact that Buchholz wanted to get the extension done was further evidence of how his priorities have evolved over time. He was well aware that he was potentially leaving plenty of money on the table. Moreover, the fact that he was giving the Red Sox control over not just a free-agent season but also two option years represented a significant potential sacrifice of value.

None of the other homegrown Sox players to sign extensions in recent years -- Jon Lester, Kevin Youkilis and Dustin Pedroia -- had to agree to more than one option year. But the Sox, according to sources familiar with the negotiations, were unwilling to budge from their position that they would need two options years.

Even so, while Buchholz said he gave "a lot of thought" to maximizing his value, going year-to-year through his arbitration-eligible seasons and then hitting free agency at his earliest possible time, he elected instead to embrace a deal that would give him long-term security. The memory of his 2008 struggles -- when he was sent back down to the minors, and his future was very much in question -- played a part in that. And, of course, there was the desire for him to assure his family long-term security in an organization that he has embraced.

"It was a difficult decision in that aspect of it, just in the fact that you play this game to be secure and make money because you're not going to be able to play baseball forever and everybody knows that," said Buchholz. "If it was me, and I didn't have a wife and a kid that I had to take care of, it might've been a decision I would've had to think about a little bit more. But from the first time we talked about it, I knew what my heart was telling me and what my family and I both wanted. That's what drove me to this decision.

"I owe a lot, just about everything, to the Red Sox," Buchholz continued. "They drafted me. They gave me an opportunity to come up in Boston and pitch even though the couple of down years. There's always going to be doubts. This game's not near as easy as some of the guys make it seem sometimes. But I definitely got to the highest point of the highs in this game, and then it took its toll on me and I thought I was better than I was at the time. Just the fact that they stuck with me through those hard situations allowed me to make this decision. It's a really good feeling."

The deal was relatively straightforward to reach, aside from the two option years. As Buchholz noted in February, the comparable contracts were obvious: teammate Jon Lester (five years, $30 million with a $13 million team option), Blue Jays left-hander Ricky Romero (five years, $30.1 million with a $13 million option) and Brewers right-hander Yovani Gallardo (five years, $30.1 million with a $13 million option) all served as the models for the type of deal Buchholz could expect.

The two sides negotiated the deal late in spring training, ironing out the details during the Sox' trip to Houston (at the end of spring training) and then to Texas to face the Rangers to open the year.

And now, the Sox have another core, homegrown player under their control for years to come. Whereas it once seemed unclear whether the team would identify Buchholz as the sort of foundational player around whom it would want to build for the long haul, that was no longer an issue.

"We see Clay as a homegrown, core member of this ballclub," said Epstein. "We expect Clay to be here for a long time and be a really big part of winning clubs. This allows him to go out and focus on the mound and do what he does best and gives Clay and his family, who is here today, some great security and gives the club some cost control and some control a little bit deeper in clay's career than the arbitration process would have afforded. We see it as a win-win. Very happy, thrilled with Clay's development from the time he signed with us to this point today, where he's a trusted core member of this club. Looking forward to many, many wins over the course of this contract from Clay."

Other notes on the deal:

--As a result of signing Buchholz to the four-year extension after the start of the season, rather than inking him to a five-year, $30.5 million pact before the year began, the Sox will save up to $1.665 million in potential luxury tax payroll this year.

--One noteworthy item for the Sox: Until this Buchholz deal, all of their control over starting pitchers ran through -- but not beyond -- 2014. The five-year deal for John Lackey and four-year contract for Josh Beckett both run through that year; Jon Lester's five-year deal runs through 2013, while the club holds an option on his services in 2014. (Daisuke Matsuzaka's six-year deal will expire in 2012.) Epstein noted that Buchholz gives the Sox a pitcher around whom it can build beyond that 2014 season; Buchholz is signed through 2015, with options for both the 2016 and 2017 seasons.

--Meanwhile, the value of homegrown pitching was on prominent display with this deal. If they stay healthy and productive, Buchholz and Lester will both represent relative bargains against their earnings. Considering that the Sox had to pay Beckett $68 million for his four-year deal, and Lackey $82.5 million over his five seasons as a free agent, the value of developing young pitching was presented in sharp relief by this deal for Buchholz. If the Sox exercise both options on the pitcher, they will be paying him $56.75 million over seven years, from 2011-2017.

"Free-agent pitching is a tough way to go. We’ve dipped into those waters," said Epstein. "If you can build an organization and not have to go into the free-agent pitching market, that’s a good thing. It’s inevitable -- you’ll have to go into it from time to time. But if you can develop homegrown pitching, control it, maybe control a couple years of free agency a little bit, that’s a very valuable thing."

Rob Bradford contributed to this report.