Despite two wobbly knees that have required surgical procedures and constant attention, Matsui has stood strong as the Yankees' reliable designated hitter, stabilizing the heart of the lineup and offering his club just about everything it could have hoped for.
"Having both knees operated on in the last couple of years and having to deal with that on a daily basis, his production has been amazing," said manager Joe Girardi.
In what could be Matsui's final year in New York, the 36-year-old entered Sunday's potential division-clincher against the Red Sox batting .280 with 28 home runs and 88 RBIs in 137 games.
Worries about Matsui's health have kept him from playing defensively, and limited him to pinch-hitting duty during the Interleague portion of the schedule. He wraps his knees in large ice bags on a regular basis, but the practice is largely preventative. Otherwise, he has been able to enjoy a season that has been both productive and relatively pain-free.
"It's huge. The fact that it's not a major issue definitely helps," Matsui said through an interpreter. "When you're playing through pain, whether you're hitting, running, playing defense or anything like that, there's always part of you that's always thinking about it and you can't quite concentrate. In that sense, right now, everything is going well."
Of Matsui's 28 homers, 27 have come as a DH, surpassing Don Baylor's club record of 25, set in 1984. Since the All-Star break, Matsui is hitting .355 (27-for-76) with runners in scoring position, making him a lethal force in pressure situations, and Girardi said that Matsui's power production has been impressive.
"He has hit a lot more homers," Girardi said. "You look at the home runs he's hit, and people say sometimes, 'It's the ballpark you play in.' He has hit them everywhere, whether we've been in Seattle, Anaheim -- tough ballparks to hit the ball out.
"I think part of it is that he's healthy, and we have not really played him eight, nine, 10 days in a row, where we wear him down. We've kept him strong, and his bat is loud. It's a different sound. That's when you know that he's going well."
Matsui slugged just nine home runs in 378 at-bats last season for New York, a campaign that saw him skip the final road trip of the season while heading for surgery. His surge this year has been a rebirth -- with seven games remaining on the regular-season schedule, Matsui is just three homers shy of tying his Major League high, 31, set in 2004, his second year with the Yankees.
"To be honest with you, I can't really quite explain it," Matsui said. "If you look at the numbers, it seems like the power numbers are there. From a mechanics and approach standpoint, I haven't changed much. Obviously, adjustments are being made every day, so perhaps in that aspect, it's good adjustments."
Despite that production, it remains entirely possible that the Yankees will not offer Matsui a contract for 2010. Because of his inability to play the outfield, his status has been cemented as a DH, a luxury the Yankees may not be able to afford with a complement of high-priced talent that could benefit from sharing the DH role.
Most prominently, Jorge Posada's switch-hitting bat might prove productive if given ample time to stay in the lineup next season, and the Yankees could keep a revolving door of options that includes Alex Rodriguez, Jeter and Mark Teixeira moving in and out of the DH spot.
Matsui has not put any heavy thinking toward the idea of not returning, though he acknowledged this spring that if that were the case, he'd at least like the chance to get back to the World Series -- a stage he saw in his rookie season, 2003, and not since.
"Right now, I'm not even entertaining those thoughts," he said. "Until the season's over, then that's probably when I would start evaluating my options."
Pressed on the issue, he allowed that his preference would be to stay with the Yankees, even though there are teams in the American League that would likely consider him as at least a DH, if not an outfield option.
"I've been here for quite a while," he said. "I like the Yankees, and I like New York. I've grown accustomed to it, so we'll see."
The Yankees have said that no decisions will be made on expiring contracts -- including those of Johnny Damon and Andy Pettitte -- until after the season. Matsui's recent performances can't help but make those decisions a little more difficult, as he is hitting .280 with 13 home runs and 41 RBIs since the first day of August.
"I feel like I've been in a better groove," Matsui said. "Before that, it was just sort of trying to see what I could do and feel it out, what I'm capable of. The last one or two months, I feel like I'm a lot closer to where I should be performance-wise.
"Hopefully, this will continue on, and if things go really well, we'll see one month from now."
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.