Last Friday, the World Champion Chicago White Sox exercised their $3.5 million buyout of Frank Thomas’s contract. Four days later, the greatest player in franchise declared his free agency. The Sox say they’d like to bring Thomas back at a lower salary (had they picked up Thomas’s option, they’d have owed him $10 million for the 2006 season), but whether they will remains to be seen.

Despite a recent spate of injuries and missed time,Thomas’s Hall of Fame credentials are beyond reproach. After 10 full seasons in the majors – from 1991-2000 – Thomas was a .321 hitter with 337 home runs, a .441 on-base average and two American League MVP awards, in 1993 in 1994.

Five years later, his career on-base percentage of .427 ranks 13th all-time, his career slugging percentage of .568 ranks 15th all-time. He’s also 17th in career walks (1,466), 30th in career home runs (448), 48th in career RBI (1,465), 74th in total bases (3,949), and 77th in doubles (447). If his balky feet and ankles are up to a couple more seasons, Thomas will likely join Babe Ruth,Ted Williams, and Barry Bonds as the only players in history to record at least 500 homers, 500 doubles, and 1,500 walks.

To put Thomas’s career in further context, let’s use OPS+, which is parkand league-adjusted OPS (on-base plus slugging percentage), and compare his mark to other active players with a minimum of 3,000 career plate appearances.The figures in the accompanying chart are the percentage of the league average OPS+. For example, a player with an OPS+ of 150 would have a parkand league-adjusted OPS that’s 50% greater than the league average.

As you can see, Thomas is unassailably one of the modern greats. Of course, the White Sox these days aren’t so much concerned with Thomas’s historical bestowals; they’re want to know what he’s capable of going forward.

Since incumbent DH Carl Everett has already filed for free agency and is highly unlikely to return, the Sox have a need for Thomas. When healthy, the Big Hurt can still rake. Last season, he batted only .219 in 34 games, but he slugged .590 and averaged a home run every 8.75 at-bats (for reference, Alex Rodriguez and David Ortiz averaged a home run about every 12 at-bats). Also, while you can clearly highlight the beginning of the 2001 season as the onset of Thomas’s decline, he’s put up a cumulative batting line of .257 AVG/.379 OBA/.527 SLG since that point. Those aren’t vintage “Big Hurt” numbers, but it’s still the equivalent of Paul Konerko at his very best.

So yes, Thomas can still hit,and if he’s able to play a full season without pain, he’s still capable of being an offensive powerhouse. But the preceding caveat is a vital one. Since 2001, Thomas has averaged only 85.8 games per year, or just a little over half a season. If you consider his age, 37, and his lumbering build, banking on newfound health is perhaps foolish.

Still, contrary to mainstream renderings, the White Sox were not a team that succeeded by virtue of “small ball” strategies. They won with pitching, defense, and power. In fact, the Sox mashed 200 homers in 2005 – one more than the Sox from Boston – and ranked third in baseball in terms of percentage of team runs generated by home runs. So they’re dependent upon power. Everett and his 23 bombs are likely gone, and although the Sox have offered a four-year, $52-million contract to Konerko, he’s bound for the free-agent market and of serious interest to well-heeled teams like the Angels and Red Sox.

If Konerko – who led the team last season in slugging average and accounted for 20% of the team’s homers – signs elsewhere, the Sox will have to replace his production. At this point, San Diego’s Brian Giles is the only “elite” hitter available on the market. With Jermaine Dye entrenched in right, the overly adored Scott Podsednik a fixture in left, and Giles not likely to accept a DH role, he’s probably not a tenable solution.

As such, the wisest tack for the Sox is probably to leverage Thomas’s sense of loyalty and comfort and persuade him to sign a low-base, incentive-laden contract for 2006, with perhaps a vesting option for 2007 thrown in. They owe it to the greatest player in franchise history, and, if Konerko walks, signing Thomas to such a contract will be a wise calculated risk on their part. Where else will they find the power on which the offense depends?

But even if Konerko returns, re-signing Thomas still makes sense. It’s not as though there’s such a dilemma having “too much power.” In 2005, the White Sox ranked a meager ninth in the 14-team AL in runs scored.That was enough offense in 2005, but having such a lackluster attack puts a heavy burden on the run-prevention side of the ledger. A healthy Frank Thomas is a boon to any team, let alone one with preexisting offensive issues. Konerko or no Konerko, the Sox need Thomas back in the fold.

To make it worth their while, the White Sox will need to make keeping Thomas healthy an organizational priority.They’ll need to pull him from the lineup religiously in blowouts,sit him during day-game-after-night-game situations, and pinch run for him almost without exception in the late innings. In short, AL manager of the year Ozzie Guillen will need to be sure he’s using Thomas as often as possible in only high-leverage situations. For Thomas’s part, he’ll need to accept that these frequent substitutions are necessary to keep him in the lineup over the long haul and refrain from complaining about them.

In human terms the Sox owe Thomas another contract – they’re the only team he’s ever played for, and Hall of-Fame-caliber loyalty deserves compensation. But it also makes sense from a practical standpoint. If Chicago is unable to lure Konerko back to the South Side, a reasonably healthy Frank Thomas is their only hope. It’s a risk worth taking.

Mr. Perry is a writer for Baseball Prospectus. For more state-of-the-art commentary and information, visit www.baseballprospectus.com.