FORT MYERS, FLA. - Francisco Liriano is 40 months removed from undergoing Tommy John surgery on his left elbow. He is back to having the top power arm on the major league roster.

On Sunday, it became official that Joe Nathan will undergo the same surgery on his right elbow. The decision was made after Nathan couldn't get through a game of catch with coach Rick Anderson without feeling stiffness in the damaged elbow.

Later, manager Ron Gardenhire held his media gathering after the Twins' 12-3 victory over Tampa Bay and suggested that Liriano's exceptional slider and 90-plus fastball gave him the best chance to replace Nathan as a dominant closer.

Gardenhire recited a résumé of power pitches before actually stating that he was talking about Liriano as a possible closer. And he said there was no chance the Twins would make the move without getting Liriano's consent.

The impression left Sunday was that the Twins will not make such an overture to Liriano until they get close to the April 1 departure from Florida. If this request comes about, Minnesota fans should hope that Liriano says, "No, thank you," and thus saves the Twins from themselves.

The Twins have a greater need for a power lefthander as a starter than they do for him as a closer. This is a team with a chance to have a very competitive rotation, but not without a revitalized Liriano in the mix.

The departure of Johan Santana after the 2007 season has left this knock on the Twins as a postseason contender: "They don't have a No. 1 starter."

Scott Baker, now 28, could be getting close to that distinction. Sunday, he cruised through five scoreless innings on one hit. There's now a confident look to go with his size, strength and quality pitches.

Kevin Slowey, 25, has returned from wrist surgery throwing his crisp collection of strikes, and Nick Blackburn, 28, has gained enough confidence from the organization to be awarded a four-year contract.

Carl Pavano, 34, is the other righthander scheduled for the rotation. He pitched 206 1/3 innings (counting a playoff start) for Cleveland and the Twins last season, a workload that seems heavy. Give Pavano an extra day between starts when possible and his arm will benefit.

Which means: The Twins rotation goes flat if there's a starter needing to be held up by Pavano.

Brian Duensing is not the answer for completing this rotation. The lefthander showed guts in making nine starts for the Twins down the stretch of 2009. The Yankees showed that guts weren't enough in Game 1 of the playoffs.

He's 27. He's competitive. He's been knocked around this spring. He's not a 30-game starter for a contending team. He's a long reliever and a pitcher to make three starts when someone visits the disabled list.

On Sunday, Gardenhire described the slider that Liriano was throwing a day earlier against Tampa Bay as "unhittable." He classified Frankie's fastball as being in the "91 [miles per hour] to 93" range. He also said Liriano is doing a better job of throwing from over the top, rather than slinging the ball haphazardly from a lower angle.

Liriano was beyond erratic last season. His pattern was to pitch a couple of strong innings, lose his motion and wind up getting an early hook from Gardenhire. Liriano was so discombobulated by August that the Twins placed him on the disabled list for what was basically a mental health break.

That woeful season has left many convinced that Liriano is a two-inning pitcher -- and thus perfect for late-inning work.

Fair enough. If all Liriano has to offer is what we saw in 2009, then giving him a chance to turn those solid first innings of last season into solid ninth innings would make sense.

That's not the way Gardenhire and the Twins are advertising the Liriano they are watching this spring. The manager was raving on Sunday about a pitcher who has his act together. He was comparing this weekend's slider to the sizzling, off-the-table variety that made Liriano the early-summer sensation of '06.

That pitcher has to be in the Twins rotation to make it competitive with the league's best.

The difference between a closer like Joe Nathan and an average closer is 4.5 percent -- Nathan's 91 percent and an average of 86.5 for all pitchers trying to close a victory in the ninth inning.

The difference between the Liriano described by Gardenhire on Sunday and the gutsy Duensing is a percentage that's incalculable.

Patrick Reusse can be heard noon-4 weekdays on AM-1500 KSTP. • preusse@startribune.com