BALTIMORE – Hours before the series finale against the Orioles, Red Sox third baseman Adrian Beltre was examining video of his swing. And he could not help but to draw in a couple of teammates.

It was, after all, something of a highlight reel of the third baseman’s power, not just as a member of the Sox, but also dating back to his days with the Mariners. And while most of the moonshots represented the punishment delivered to mistakes, there were some that fell into the “only by Beltre” category. Most notably, there was a pitch over the slugger’s head that he launched over the fences.

“That is the pitch,” said Beltre’s teammate, “that I’m going to get you out with.”

The statement was playful, yet under the circumstances, potentially loaded with meaning.

Beltre – who jumpstarted the Red Sox’ offense on Thursday with a solo homer (his 25th) that sparked a five-run, second-inning rally in his team’s 6-4 victory over the Orioles (recap) – is a free agent after the season. He has been the best player on the Red Sox, and indeed one of the best all-around players in the game in 2010 by most measures.

Fangraphs.com, for instance, ranks Beltre eighth in the majors in runs above replacement player and wins above replacement player, putting him in a near dead heat with Albert Pujols and Evan Longoria.

Meanwhile, his teammates have marveled at what he’s contributed this year.

“He’s been great, obviously,” said Victor Martinez. “He’s helping this team, big time. He’s been pretty much carrying this team all year.”

“The most consistent guy on our team. He’s been the MVP of our team,” added Kevin Youkilis. “He’s done an unbelievable job.”

This season has been, in many ways, a revelation. Beltre arrived with the reputation for defensive excellence. Despite a surprising number of errors, he has dazzled his teammates with his work in the field.

Yet it is his offense that has seemed most surprising. While that aspect of his game has most dramatically exceeded public expectations, however, at this point, it may be more interesting to reflect on the degree to which the season by the free-agent-to-be has not been a surprise.

Though the Sox did not expect that he might feature a .321 average that would place him in the top five in that category in the American League, they did expect that the loss of power that the third baseman experienced in 2009 was completely the result of some debilitating injuries. First, there were bone spurs in his shoulder that required not one but two surgeries. Then, there was the bruised testicle that felled him late in the season.

With those injuries consigned to his past, the Sox had every expectation that they were acquiring a third baseman with some serious pop.

“He’s always hit for power. He was moving into a good lineup and a good hitter’s park. We expected him to hit for above average power. We certainly thought that 25 or 30 was in the realm of possibility,” said Red Sox GM Theo Epstein. “We thought he’d be a guy who put the ball in play a lot, hit for power, drive in runs and obviously play really good defense.”

The 31-year-old has a track record as a hitter who collects plenty of homers. Beltre has now hit 25 or more homers in four of the past five years (his injured 2009 campaign representing the only season in which he’s failed to hit that mark). Only one other third baseman -- Alex Rodriguez -- can make the same claim.

And while the likelihood is that Beltre may not be a perennial .320 (or even .300) hitter, he is hitting the ball with such force that he has remained a formidable lineup presence even when not featuring a batting average more normally associated with Ichiro.

To wit, since the beginning of July, Beltre is hitting just .282 with a .326 OBP. Those numbers are fairly close to his career norms of .274 and .328.

Yet he has launched 13 homers in the two-month span. As a result, his slugging percentage (.553) and OPS (.881) have remained robust over that stretch. Those have left him with a year-long line of .321/.362/.556/.918 with 25 homers and 92 RBI.

His production is all the more noteworthy in that he has played much of the second half dealing with injuries, most notably to his hamstrings. Aside from the fact that he has been limping on the base paths of late, there has been little evidence of his discomfort, and plenty of evidence of his ability to thrive as a member of the Red Sox.

“The biggest thing is he’s done it not 100 percent. That’s probably the most impressive part of the whole thing,” said teammate Jon Lester. “The guy’s played banged up all year.

“I think his style of play fits Fenway Park. He hits a lot of high fly balls. I think that plays well in our park. He obviously has the power to drive it out to right-center and right field. Obviously, his third base abilities are self-explanatory. It would be nice to have him back.”

Right now, the game of figuring out whether the Sox might re-sign Beltre is an act of pure speculation, aside from suggesting that, barring some highly unforeseen circumstance, he will decline his $5 million player option, even if it increases to $10 million should he reach the now-attainable mark of 640 plate appearances.

Beltre, a Scott Boras client, is also all-but-certain to test the free-agent waters before discussing a return to Boston. As the elite third baseman on the market, he will be coveted.

Will there be alternatives should Beltre head for greener pastures (and dollar figures) this coming offseason? Of course.

While Beltre would clearly be the standout third baseman on the market, Kevin Youkilis could afford the Sox the opportunity to pursue either a first or third baseman. That would give the team fallback options in the form of players like Adam Dunn, Adam LaRoche, Carlos Pena and (though unlikely to leave Chicago) Paul Konerko.

For his part, Youkilis would be open to moving back to third, though he would prefer that his day of shuttling between corners be over.

“I don’t care where I play,” said Youkilis. “We’re better as a team when guys aren’t shuffling all around. The situation got addressed [by signing Beltre], and that’s why the situation is the way it is. The situation got addressed last year, and I don’t think it will be a problem down the road.”

Whether or not he comes back remains to be seen. Clearly, he has shown an ability to perform in Boston, and he has proven himself to be an impact player.

Given what he has been, it would be hard to imagine any other corner infielders on the free agent market making the kind of impact that Beltre has produced in his lone season in Boston.

“He’s certainly been tremendous for us,” said Sox manager Terry Francona. “I hope we continue to talk about it. He takes some ferocious swings and just continues to go out there and play great baseball.”