Shuffling the pitchers

P.J. Walters collects himself before throwing his first
pitch Wednesday against the New York Yankees.

The Twins have swapped out a starting pitcher and rebranded some bullpen roles. Let's look:

P.J. Walters designated for assignment: Mike Pelfrey is coming off the disabled list to make Saturday's start. The Twitter buzz from the beat writers this week suggested that both Walters and Scott Diamond were pitching for their jobs in the Yankees series.

Diamond went 6.2 innings, allowing three runs (two earned); he also had, according to Baseball reference, more groundballs than fly balls for the first time in four starts. Diamond lives on the grounders, and his GB rate this year is closer to average that top-of-the-charts, as it was last year.

For his part, Walters went five innings, allowing three runs, all earned. And it was Walters who lost his job.

Which, if it was indeed down to Diamond vs. Walters, the right choice. Neither man is gifted with overwhelming stuff, but Diamond has more markers in his favor (not the least of which is being left-handed).

Walters is out of options, and Diamond is not, but the call apparently wasn't close enough for that tow sway the decision. So now Walters enters the 10-day limbo of DFA and waits to see what happens.

Duensing, Burton slide down the bullpen hierarchy: The Twins eight-man bullpen has had two castes this season: The four late-and-close guys (closer Glen Perkins, set-up man Jared Burton, and middle men Casey Fien and Brian Duensing, who are generally used for fractional innings to get out of jams in the sixth and seventh), and the four longer men (Josh Roenicke, Anthony Swarzak and rookies Ryan Pressly and Caleb Thielbar).

Burton had a rough June (ERA 7.45 for the month) and he opened the new month by giving up three runs in one-third of an inning in Game 1 of the Yankees series.  So now Fien is supposedly going to be the eighth-inning guy while Burton works in lower-leverage situations.

It's less clear who gets the ball in Fien's customary role, which isn't exactly low-leverage. The Twins like a power arm in that job, and I would think that points to Pressly. But (a) they might prefer to give the veteran Roenicke the first shot and (b) Pressly hasn't been all that effective of late either.

Ideally Burton straightens things out quickly and reclaims the eighth-inning role. Fien may be just as good in that role as Burton, but the options for Fien's accustomed role are thin.

Caleb Thielbar has
walked seven and
allowed five hits
in his 18-plus innings.

Similarly, Thielbar has supplanted Duensing in the left-handed set-up role. Duensing, who has been death on left-handed hitters for most of his career, has not been nearly as effective this year (.292 batting average allowed to lefties).

Thielbar hasn't been charged with an earned run yet in the majors (18.2 innings), although he has allowed some inherited runners to score. Nor, through 16 games, has he ever been brought in with a lead.

So far, Ron Gardenhire has used Thielbar much as he used Craig Breslow in 2008. Dennys Reyes was Gardy's primary LOOGY (Left-handed One-Out GuY), and the manager wouldn't use Breslow in game situations. Pigeonholing Breslow into low-leverage situations only was one reason the Twins didn't win the divisional title that year.

The Twins aren't winning the division this year no matter how Thielbar is used. But maybe a lesson has been learned.