Counting down to spring training: Designated hitter

David Ortiz (turned 33 in November)
2008: .264 batting/.369 on-base/.507 slugging
2007: .332 batting/.445 on-base/.621 slugging
2006: .287 batting/.413 on-base/.636 slugging

Roses are red,
Rubies are, too;
If Big Papi sees his power production keep dwindling as he gets older until he's suddenly no longer useful a big-league hitter because nagging injuries are robbing him of his power,
Sox fans will be blue.

Or something like that.

Some fans worry about Ortiz's wrist. Some worry about how he'll fare without the protection of Manny Ramirez for a full season. (Then again, Ortiz OBP'ed .360 and slugged .498 before Ramirez was traded on July 31; he OBP'ed .381 and slugged .519 after the trade. Take that for what it's worth.)

But many fans have to worry about something else: Mo Vaughn.

Vaughn, like Ortiz, was one of the American League's most ferocious power hitters for the better part of a decade. His numbers leading up to his 30th birthday look eerily similar to Ortiz's over the same time span:

Ortiz: .283/.374/.550, 231 home runs, 763 RBI, 622 runs scored
Vaughn: .304/.394/.542, 230 home runs, 752 RBI, 628 runs scored

Vaughn, at that point, cashed in on his third MVP-caliber season in four years and signed an $80 million contract with the then-Anaheim Angels. His ankle injury in his first game with the Angels has been well-chronicled, but he still hit 33 home runs and drove in 108 runs in 139 games that season. A year later, in 2001 at the age of 32, he played in all but one game and hit 36 home runs with 117 RBI.

He then missed the entire 2001 season with a ruptured tendon in his left arm and subsequently was traded to the New York Mets. He had to fight an assortment of nagging injuries -- the type of injuries 34- and 35-year-old players often have to fight -- and hit a combined 29 home runs in two seasons with the Mets before hanging it up for good.

Cecil Fielder, another player with a body type in the Ortiz mold, hit 39 home runs at the age of 32 -- his highest total in five years -- but saw things go rapidly downhill after that. His slugging percentage dropped from .484 in 1996 to .410 in 1997 and .401 in 1998, and he retired after the 1998 season. Fielder was a slightly different type of player -- he never hit for average like Ortiz and Vaughn -- but his career trajectory is another warning flag.

Ortiz has seen his slugging percentage dwindle in back-to-back seasons since turning 30. His wrist injury contributed significantly to that; all indications are that he's healthy and ready for a bounce-back season. But he'll be 33 this year, and 33-year-old power hitters often find themselves hampered by a new injury every time they recover from an old one.

Big Papi certainly could have a big season this season. Jason Giambi, after a rough year at the age of 33, hit 32 home runs at age 34 and 37 home runs at age 35. Carlos Delgado, who appeared to be finished as recently as last spring, finished last season with 38 home runs at the age of 36.

But once a power hitter gets to be 33 years old, history says he's living on borrowed time. The Red Sox certainly know that. Ortiz is under contract for this season and next season with a $12.5 million team option for 2011 -- an option that is unlikely to be picked up.

The Red Sox can't afford to be nostalgic with Ortiz, who almost singlehandedly turned around the fortunes of the franchise five years ago. Vaughn hit a grand total of 29 home runs after his 33rd birthday. Fielder hit a grand total of 31 after his. George Scott, the predecessor to both Vaughn and Ortiz, hit 33 home runs at the age of 33 but a total of just 18 after that.

Once it starts to go, it goes in a hurry -- and the Red Sox are going to have to be prepared when it does.