The Twins took a nine-game winning streak in Target Field and a 24-8 record since the All-Star break into Thursday night's game with the Chicago White Sox. The possibility of a sweep that would push the Twins' lead to six games in the American League Central made for rampant optimism among the customers.

It also overshadowed a glitch that has appeared in the Twins rotation -- and this time at the front end rather than the back.

The Twins went into the All-Star break at 46-42 and trailing both the White Sox and Detroit. Nick Blackburn and Kevin Slowey established themselves as worthy candidates to be removed from the rotation.

Blackburn started the first game after the break on July 18 and was pummeled by the White Sox in Chicago. That put him in the bullpen and then Class AAA Rochester, with lefthander Brian Duensing taking that slot.

Duensing has made five starts with increasing effectiveness -- capped by last Saturday's shutout of the Oakland A's. And Slowey has taken a similar path since being spared demotion, with five consecutive starts that have ranged from OK to very good.

That took care of the Nos. 4 and 5 holes in the rotation, with Carl Pavano and Francisco Liriano, the co-aces of 2010, and Scott Baker, theoretically the No. 1 starter in 2008 and 2009, still available to lead the charge.

And that's where the glitch has surfaced:

• Pavano had back-to-back complete game victories over the White Sox and Baltimore on July 17 and 22. He made his fifth start since those masterful efforts on Thursday. The result was an 11-0 White Sox victory in which Chicago had a 21-5 advantage in hits.

Pavano was matched against Mark Buehrle, the White Sox's indomitable lefthander. They had faced off July 17 at Target Field, and Pavano beat Buehrle 3-2 in a 1-hour, 52-minute track meet.

This time, it took Pavano 15 minutes to get through a top of the first in which he gave up two runs and four hits. He wound up lasting six-plus innings and was scalded for 15 hits -- a total that equaled a Twins record shared by Brad Radke and Geoff Zahn.

Over his past five starts, Pavano has worked 30 1/3 innings and given up 46 hits, 10 walks and 16 runs. Clearly, the Pavano the Twins saw regularly from April 7 through July 22 looked nothing like the veteran they have seen since July 27.

Could be that it's time to lose the mustache.

• Liriano came out of the break in outlandish fashion. He made three starts in a row in which he did not allow a run. This culminated with seven innings in which he gave up two hits and struck out 11 against Seattle on Aug. 1.

On Wednesday, Liriano needed 106 pitches to get through five ugly innings against the White Sox. He gave up six hits, four walks and five runs -- and was saved by another Twins rally.

He hasn't had that elusive delivery in synch for three starts, totaling 15 1/3 innings and giving up 20 hits, 12 walks and 10 runs. The cure for Francisco sounds easy, but it never has been: getting him to stay back and throw strikes, rather than jump toward the plate and scatter pitches everywhere.

• And then there's Baker. The Twins gave him a 4-0 lead in the first inning on Tuesday, and he couldn't wait to start giving it back.

He's had two strong starts among his past seven. He has had nothing resembling a hot streak, and only 10 quality starts among 24.

Thursday, there was a pregame conversation about Matt Capps, the closer obtained at the end of July. Manager Ron Gardenhire was asked: "Was a reliever your top priority at the trading deadline?"

Gardenhire said: "We wanted pitching help. Andy [pitching coach Rick Anderson] and I thought we really need another good reliever. We were more confident that we had starters that could be fixed."

Over five starts, Duensing has filled one hole and Slowey has turned around his season. But as St. Louis pitcher Joaquin Andujar famously said, "youneverknow," and now the Twins have to do their fixin' with Pavano, Liriano and Baker, the starters that are supposed to be Nos. 1 through 3.

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