The most fascinating drama available to Minnesotans is not an AMC miniseries. It's not an election or stadium debate. It is a one-man play running on a limited engagement in downtown Minneapolis, one featuring the inscrutable interior monologue rattling around Francisco Liriano's head.

For years, everyone has worried about his elbow when what goes on in his cranium is so much more interesting.

Friday night, Liriano wowed the scouts at Target Field. He struck out a career-high 15 batters in eight innings, displaying a vintage slider that dove like a bird of prey.

He also lost his concentration for a few moments, because of an error, a grounder off his foot or maybe a particularly distracting butterfly, and in two at-bats lost the game.

Jemile Weeks started the fourth with a hard grounder up the middle that ricocheted off Liriano's left foot for an infield single. Liriano struck out Josh Reddick for the second time, then Yoenis Cespedes flew to center. Denard Span bobbled the ball for an egregious error.

Liriano walked Chris Carter to load the bases, then allowed a grand slam to Jonny Gomes.

Span will get most of the blame, but Liriano has a knack for making a bad inning worse and spoiling his own most impressive outings.

Friday, he again faced adversity and cringed.

That is why contenders should be wary about trading for him. That is why those who have reacted to Liriano's recent success with suggestions that the Twins should sign him to a contract extension should go back to fantasizing about Tim Tebow and Jeremy Lin winning championships.

Liriano had remarkable stuff. He was facing the worst-hitting team in the American League. He was as dominating as he has been in any start since 2006. And he couldn't avoid a game-defining brain cramp.

That's not a good sign if you're scouting him. The teams that would want to trade for Liriano would be counting on him to pitch well in Yankee Stadium, or against the Rangers' lineup, in the crucible of a pennant race.

Some pitchers require run support. Liriano requires moral support.

Entering Friday's game, he had a 2.60 ERA while pitching to his personal catcher, Drew Butera. His ERA when pitching to Joe Mauer: 8.75. When pitching to Ryan Doumit: 10.57.

If only Liriano were as capable of keeping baseball simple as Josh Willingham.

Liriano entered the 2012 season in the final year of his contract. "Contract year" is synonymous in pro sports with overachievement, as the athlete performs his best while motivated by the promise of a big payday. He had every reason to excel.

His ERA in April: 11.02.

Willingham entered the 2012 season with a new, three-year, $21 million contract. Often ballplayers, after signing new deals that will make them financially secure for the rest of their lives, lag either because they can't handle the pressure that comes with the contract and playing for a new team or because they become complacent.

Willingham, in a ballpark that has been tough on power hitters, launched two more home runs on Friday night. He has 21 this season, more than any Twin hit all of last year.

The difference between the two is their approach.

Willingham is a grinder. He's played in more games than any other Twin. He knows that his value to the team is in pulling the ball a long way, so he builds his at-bats around the search for a pull-able pitch.

Liriano is more gifted than Willingham. He would be valuable to a contender because the team acquiring him would be replacing a presumably struggling fifth starter with a pitcher with excellent stuff.

The fourth inning showed why scouts might want to include a few qualifiers when praising Liriano. He is hard to trust.

If the Twins were foolish enough to re-sign Liriano, they would need to add Butera in a package deal.

Liriano would get the money to the left of the decimal point, and Butera would get the money to the right.

Jim Souhan can be heard Sundays from 10 a.m. to noon and weekdays at 2 p.m. on 1500-AM. His Twitter name is SouhanStrib. • jsouhan@startribune.com