PHOENIX – When the Red Sox picked up the $12.5 million option on David Ortiz’ contract for the 2011 season, there was a sense that the team was doing the longtime slugger a favor. Ortiz could still be an important hitter in a lineup, but gone were the days when he ranked among the game’s elite power hitters. It seemed almost impossible that his production could match his salary, at a time when the DH market seemed to be drying up.

Guess again.

Ortiz arrived at the All-Star Game on Monday illuminating the festivitaties as one of the game's undeniable stars. On the stage of the Home Run Derby participants -- a group that included such stars as Blue Jays basher Jose Bautista, teammate Adrian Gonzalez and Brewers slugger Prince Fielder -- Ortiz had the high-wattage presence of a star, carrying himself with the confident air of a player who has little doubt about his place in the sport.

Ortiz is amidst his best season since 2007, and he is posting the sort of numbers that resemble what he did in his initial years in Boston. He has been a middle-of-the-order beast with whom to be reckoned.

With the baseball world taking its midsummer break, Ortiz has put up numbers that rank among the best in the game. He is hitting .306 with a .391 OBP (7th in the AL), .574 slugging percentage (4th), .965 OPS (4th) and 19 homers (7th). His 43 extra-base hits are third in the AL.

He is making as much consistent, hard contact as nearly any hitter in the American League save for Bautista and teammate Gonzalez. And in the process, he is reasserting himself in a fashion that suggests just how hard it would be to replace him.

While there is a commonly held view that DH is the easiest position to address because a team simply needs to sign a good hitter and stick him in that gloveless job, the offensive standard that Ortiz – a free agent after this year – is setting in 2011 suggests that it would be incredibly difficult for the Sox to replace his production if they do not re-sign him.

“To find a hitter that can produce like you want a DH to produce, those guys don’t grow on trees,” said Lance Berkman of the Cardinals. “I mean, can you replace what David Ortiz does in Boston with just anybody? Absolutely not. He’s a great hitter. Those guys don’t just come around. Where are you going to find another great hitter like that?”

So what might the Sox find on the market if they were to let Ortiz head elsewhere in free agency this winter? The returns on last offseason’s DH maneuvers offer a grim view.

Last winter saw two different approaches to addressing a need at DH. A couple of teams went the high-end route, signing players to expensive multi-year deals for money along the lines of what Ortiz is making in the option year of his Red Sox contract. Most clubs dipped into the bargain aisle to sign designated hitters to short-term contracts.

The results:

--The Tigers committed four years and $50 million to 32-year-old Victor Martinez, and for that hefty long-term investment, they have gotten the most return on their initial investment to date. Martinez has been a solid middle-of-the-order presence, albeit one whose numbers don’t compare to those of Ortiz.

The ex-Sox catcher has an excellent average (.316), but otherwise has a .362 OBP, .457 slugging mark, .820 OPS and six homers. While Detroit is getting some work behind the plate from him (he has caught in 23 of his 77 games this year), Martinez almost certainly will see his playing time tilt more dramatically to DH (with a few games at first base) as his contract progresses.

--The initial returns on Adam Dunn’s four-year, $56 million deal with the White Sox likely have been terrifying for Chicago. The 31-year-old has the worst batting average in baseball (.160), while the slugger’s OPS of .597 ranks 193rd of 200 players who have had at least 250 plate appearances this year.

Dunn represented a case of a team taking a player who had a lengthy history of offensive production and a brutal glove and assuming he could DH. It is difficult to say whether his struggles are related to his efforts to adapt to a new role, but regardless, the first half-season of his four-year deal with the White Sox has been dreadful.

-- The Orioles signed Vlad Guerrero, coming off an All-Star season with the Rangers, to a one-year, $9 million deal for his age 36 season (the same age that Ortiz will be next year). He has represented a relatively easy mark in Baltimore’s lineup, with a respectable .279 average masking his awful .315 OBP and .700 OPS.

--The Athletics went the bargain route, signing Hideki Matsui to a one-year, $4.25 million deal. The 37-year-old has performed like a player whose career is nearing its end, hitting .209 with a .617 OPS and six homers in 300 plate appearances.

--Jim Thome, at the age of 40, seemed like a bargain for the Twins to re-sign for a year and $3 million. Yet after he had a huge 2010 campaign, Thome has played in just 40 games this year while hitting .219 with six homers and a .780 OPS.

So what free-agent options would exist for the Sox if they decided that they either felt that it was time to let Ortiz move on after this season or if they failed to find common ground with Ortiz in negotiations? Based on the Sox slugger’s resurgent first half, not many.

The first is Prince Fielder, the Brewers first baseman who has been true to his career track record of crushing opposing pitchers. Fielder is hitting .297 with a .415 OBP, .575 slugging mark, .990 OPS, 22 homers and an NL-leading 72 RBI.

Fielder, who served as Ortiz’ counterpart as the captain of the NL squad in Monday night’s Home Run Derby, took stock of Ortiz and marveled at what he’s been able to do as a DH.

“He’s awesome. Especially doing what he does DH-ing,” said Fielder. “I did it a little in interleague. It’s not easy to do that. Especially to put up the numbers he does. I think he’s a great hitter, and he’s just really awesome.

“[Being a DH is] different because you can’t have the sweat from playing defense. You have to have a routine to get loose. It’s not like you play defense, come in and you’re still warm. It takes effort to keep your body ready. It’s even harder mentally.”

That said, as he prepares to reach free agency following his age 27 season, Fielder did not rule out the possibility of signing with a club as a DH.

“I’m not really ruling anything out,” said Fielder. “It’s tougher [than playing first base], but I didn’t mind it. … It’s something you have to learn. It’s not something you can do and expect to be good without having to make any adjustments.”

Yet while Fielder isn’t ruling out being a DH, as a 27-year-old who consistently numbers among the top sluggers in the game, he will come at a significant cost this winter in both free-agent dollars and years. If the Sox decide that they want to move on from Ortiz in order to reallocate money away from the DH role, Fielder – who could command a salary of upwards of $20 million – would seem an unlikely target.

The other free agent-to-be who has delivered production along the lines of Ortiz is Berkman, who is having a monster year for the Cardinals. Berkman floundered a bit with the Astros and Yankees in 2010 (his tenure in New York having given him his most extensive taste of life as a DH), but he has come back with a vengeance this year in St. Louis.

After he signed a one-year, $8 million deal with the Cardinals, Berkman has re-asserted himself as an All-Star, hitting .290 with a .404 OBP and NL-leading marks in slugging (.602), OPS (1.006) and homers (24) while shuffling between first and the two corner outfield positions.

Berkman has experience as a DH, and considered signing in that role with the Rangers last winter. Still, it would appear that all things being equal, the 35-year-old prefers position play to the role of full-time masher.

“I’m not a fan of the DH,” said Berkman. “I think they should get rid of the DH, period. … [Being a DH] certainly takes a little bit of getting used to. The mental challenge of it really is the thing.

“You have a tendency when you’re not playing in the game, your mind wanders, you’re not locked in and then all of a sudden, ‘Whoa – it’s my turn to hit, and now I’ve got to focus again.’ It’s something, I think, that takes a little bit to get used to. It’s not like a whole year – it shouldn’t take that long. But it certainly takes a little bit of an adjustment period.”

Among the class of impending free agents, the next two in terms of OPS this year are shortstop Jose Reyes (who will not be DH-ing anytime in the next several years) and Carlos Beltran (with an .880 OPS), followed by Cardinals masher Albert Pujols (.857).

Of course, it may be a bit misleading to compare the class of free agents to what Ortiz has done in 2011, since this season represents a jump from his performance of the prior two years, in which he’s remained a power threat but has endured prolonged slumps that hurt his numbers.

Still, if one looks at Ortiz’ three-year performance since 2009, he has hit .265 with a .359 OBP, .512 slugging mark and .872 OPS while averaging 34 homers and 109 RBI per 162 games. Pujols, Fielder and Berkman are the only impending free agents who have higher OPS totals; Pujols and Fielder are the only potential free agents aside from Ortiz (who has gone deep 79 times) who have as many as 70 homers since the start of 2009.

In other words: It appears that if the Sox do elect to let Ortiz go, they will find it more difficult to replace him than many envisioned at the time that the club was making the decision about his option last winter.

Of the potential free agents from whom similar production can be expected, most would come at a massive cost in years and dollars. All would have to face the uncertain life of a transition to a new role that isn’t as effortless to embrace as many believe.

There will, of course, come a time when the Sox move on from Ortiz. And certainly it would be difficult to look at Ortiz’ tremendous first half and to project that he can perform at this level going forward. Nonetheless, it is difficult to deny that Ortiz – after all these years – still appears to represent something of a hand-in-glove fit with the DH role in Boston, and that the challenge of replacing him, if it comes to that, would be immense.