But the bat abandoned him badly last year, thanks to a combination of injuries, a spacious home ballpark (Safeco Field) and perhaps even a loss of confidence.
Set to make his new home at Fenway Park, which can be a haven for right-handed pull hitters, Beltre is confident that his 2010 highlight reel will consist of a lot more than web gems.
"I hope it helps," said Beltre. "There's some parts of Safeco than can be frustrating. It's a beautiful ballpark. But as a hitter, sometimes you make contact and you expect a little better result. It didn't work out that way. Sometimes you're going to take a hit on your at-bats if you're not confident. Sometimes you hit a ball and think it will be a gapper or maybe a homer and it ends up being an out. Next at-bat, you probably think about trying to hit it a little harder. That's where the problem comes, creating some bad habits. Maybe that won't happen here."
In truth, if it wasn't for Beltre's sharp downturn at the plate last year -- when he hit .265 with eight homers and 44 RBIs in 449 at-bats -- he likely would have had his unveiling somewhere other than Fenway. If he had hit last year, he wouldn't have fit into Boston's payroll structure.
So what ensued is what appears to be, at the very least, a perfect short-term marriage. Though Beltre had multiyear offers from other teams, including a three-year proposal from the Oakland Athletics, agent Scott Boras was much more interested in seeing his 30-year-old client re-boost his value in 2010 under a shorter-term deal.
The Red Sox, who had already stretched their budget with the signings of John Lackey, Marco Scutaro and Mike Cameron, were looking for a short-term deal. Not only that, but they have spent their winter trying to improve their defense and run prevention, where Beltre will pay large dividends.
As they've shown the ability to do in past dealings, Epstein and Boras got creative, striking a deal that was both team- and player-friendly. Beltre will earn $9 million in 2010. He has a player option for $5 million, which jumps to $10 million with 640 plate appearances. In other words, if Beltre has the year he's planning on, he can again test free-agent waters next year, when his value has been increased.
"It's really something where Adrian has been very successful at a young age," Boras said. "Economically, he can afford to turn down guaranteed money to come here on a one-year situation. Theo and I have learned a little more about the collective bargaining agreement and how to do things to manage this deal and to put a creative venture together. I think we've built a great stage here and there's a chance for this rocket to take off."
While reaping near nightly benefits from Beltre's glove, the Red Sox also think there will be some thump from that bat, which averaged 25 homers and 88 RBIs between 2006-08.
"We think Fenway is a fit for Adrian," said Epstein. "It's hard to emphasize just how much Safeco deflates offensive performance for right-handed power hitters. It's really a tough place to hit. Mike Cameron, I know, talked about it when he was in here. It's a difficult place to put up any kind of numbers, left field, left-center, center field, even if you hit the ball well to the opposite field, it's hard to get rewarded as a right-handed hitter there.
"Obviously Fenway is a nice place to hit if you can elevate the ball to the pull side. It also doesn't take away from a nice opposite-field stroke. Adrian's natural stroke sometimes is to the opposite field, which is fine. He'll be rewarded here in the gaps. Pull-side elevation will obviously be rewarded."
But yes, the defense, that is truly what drew the Red Sox to Beltre. Epstein noted how five years ago, he tried to sign Beltre as a free agent, with the plan of playing him for one year at shortstop while Bill Mueller finished out his contract in Boston. But Beltre, coming off a monster year with the Dodgers, instead went to Seattle.
"I think Adrian's reputation is that he's one of best defenders in the game, period, let alone one of the best defensive third baseman," Epstein said. "He's got all the attributes you look for in a third baseman. He's got quickness, he's got great hands. His feet are tremendous. Great arm and very quick release. He has that signature play coming in on balls, which he does better than maybe anyone in the history of the game. He attacks the baseball. He's really a weapon defensively and we're looking forward to having him help our run prevention."
Beltre is looking forward to a healthy 2010, something that couldn't be said for last year, when his left shoulder throbbed before the surgery to remove bone spurs on June 30.
"Obviously I passed the physical," Beltre said. "I'm 100 percent. My health is good. I'm really excited to come out and prove that I'm healthy and contribute to this team and hopefully win the World Series here."
As much as he enjoyed his five years with the Mariners, the one thing he didn't much like was missing the postseason each year. The last and only time he tasted meaningful October baseball was in 2004, when his Dodgers lost to the Cardinals in four games.
"It's true, I had many multiyear offers, but I made the decision to come here and take my chances with a team that has a legitimate chance to get to the World Series," said Beltre. "I've been in the big leagues for 11 years and have only been in the playoffs once. I like my chances. I like the organization and I like what's going on here. I think the team is built to win. It's a decision I made and I'm really happy about it."
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.