[ATTACH=CONFIG]5043[/ATTACH]Left-handed relievers are a valuable if not under-appreciated members of society. You know, like oxygen. While they may seem ubiquitous and always available, a team could get killed if you don't have any.

They have a certain vampiric quality to them as they are seemingly able to last forever while continually finding work. Darren Oliver, 37-years-old, has been employed steadily. Despite mixed results, J.C. Romero has hung around baseball. Even with numerous options out there, when the trade deadline comes around, contending teams rush out to acquire one or two for safe measure.

Because of this it is possible that Minnesota Twins’ reliever Brian Duensing may have thrown his last pitch with the team on Wednesday night.

Admittedly, Duensing does not quite fall into that category of a specialist. In the recent past, he had been able to dominate same-sided opponents with a big slider. Judging by that alone, it appeared that he would make a strong left-handed reliever. After bouncing from the rotation to the bullpen thorough out his five years with Minnesota, 2013 has been the first year he has been a full-time reliever. And this season he has been asked to retire lefties more than the previous years.

“The only thing I feel like is really different, is the fact that I am more focused strictly on the lefties,” says Duensing in regards to his approach. “I’m not coming in worrying about the righties as much, but I’m facing righties a little more than I did earlier in the season. The main thing is that it is kind of hard, at this very moment I don’t have the feeling that I know exactly where it’s going to go all the time. Which is fine: If I don’t know where it’s going, they don’t know where it’s going.”

This admission, when synchronized with Mike Moustakas’ eighth inning solo home run on Wednesday night, would highlight Duesning’s shortcoming this season. Catcher Joe Mauer would call for the standard slider down and away to the left-handed hitting Moustakas but the pitch would be up and middle-in and wind up just inside the right field foul pole. To be sure, the home run was a rare display off of Duensing – just his second allowed in 2013 – yet command issues are noticeable.

The transition to the bullpen has allowed Duensing to air it out constantly knowing that he will have a short outing, more so this year than before. After averaging 4.0 outs per appearance from 2009 to 2012 while in relief, he’s down to 2.4 outs per appearances this season. As such he’s hitting closer to 93 on the gun. Of course, the trade-off may be the decline in precision. For instance, the lack of command has been prevalent in Duensing’s overall peripheral numbers. After walking just seven percent of all batters faced, the lefty has issued free passes to ten percent of hitters this year.

So does he believe the fastball -- when trying to rear back and attempt at triple-digits on the radar -- is the culprit? “It’s basically all of them. It’s kind of scary but, as of lately, the results have been a little better.”

For the most part, sure. After all, Duensing had been stringing together a good series of appearances. In seven appearances from July 9 to July 26, he had not allowed a run to score. However he was playing with fire in several of those outings, allowing four walks and a hit batter in 6.2 innings and last night, he struggled to retire four Royals lefties in a row.

Duensing seems content with his role in the bullpen but acknowledges the challenges of transitioning from a starter to a reliever takes preparation.

“It’s not easy to come to the ballpark everyday and be prepared to throw. As a starter you have four days off in between, so mentally it is kind of taxing on you to try to figure out when you are going to pitch. Every day you might pitch. You might throw three, four days in a row or you might not throw for five.”

The move is not always as simple as it would seem. In 2011 while with the Twins current Miami Marlin Kevin Slowey was reassigned to the bullpen but struggled with his new role. Some research has indicated many pitchers have moved from starter to reliever and not only have done well but thrive with added velocity or a specialized role. Look no further than Duensing’s current bullpen mate Glen Perkins who has rebounded as a fallen starter to a reliever with a mid-90s fastball and devastating slider, eventually becoming an All Star closer. On the other hand, others cannot clear the preparation hurdle. That was Slowey’s biggest downfall. Manager Ron Gardenhire noted in May of that season that they would call down to the pen to get Slowey ready he would throw “five or six pitches” then say he was ready. The results would be that Slowey would need a few days of rest afterwards.

There is a reason why marathon runners do not always make good sprinters.

More often than not, Gardenhire has been consistent with Duensing’s usage in 2013 and Duensing has given him no indication that he is not equipped to handle that sort of treatment. According to Baseball-Reference.com, 31 of Duensing’s appearances have come with no days or one day off between outings. In his 10 appearances with no days of rest in between, he has limited opponents to a .257 average and just two runs. Although not quite the rubber band man that Matt Guerrier was during the late 2000s heydays, Duensing has demonstrated he can be ready when needed, a fact which he attributes to preparing for the marathon of starting and adjusting for the sprint of the bullpen.

“In the offseason, I prepare like I’m going to start,” he says. “ Obviously, it is a lot easier if you are prepared to go long, it’s a long easier to go short. During the season, like when they said I was going to be in the bullpen, I changed my mentality and the throwing I do – you are not playing long-toss every day, you are kind of shortening up here and there and you are really paying attention to how your arm and body feels and how it is working, ‘cause you have to be ready to go every day, so you have to make sure you know what it takes to make sure you are ready to go.”

Duensing, now in his fifth season in the majors and will have his second year of arbitration this offseason, says the experience has helped breed familiarity with his opponents – something that can be both good and bad.

“There are some guys I feel comfortable knowing how I want to go about pitching them. There are some guys who I still may not have a good idea about. I am also noticing that I may have fallen into patterns the last few years – like I noticed a lot of lefties try to take the same kind of approach on me.”

The book for left-handed pitchers says to stay away from lefties – bust them on the outer-half of the plate with fastball and breaking pitches. Duensing started to feel that same-sided opponents were cheating a bit and going with that pitch. Instead, he has been trying to go inside to left-handed opponents more.

“I’ve had a lot of success going in on lefties. So I don’t know if that means the ball is running a bit more or if they are looking middle-away, I feel like that is a typical way a lefty would pitch a lefty, away with sliders and fastballs. I try to get out of my normal patterns and keep them guessing.”

Like on Wednesday night, Duensing sawed off former college teammate and groomsman Alex Gordon’s bat into a toothpick on a fastball inside. However, Gordon won the battle with his friend with a liner the other way when Duensing would go back outside with a fastball that stayed away but up in the zone.

When asked if he has ever reviewed pitchf/x data, Duensing said he had brief encounters with the numbers but had not explored anything to any extend, he has felt more comfortable trying to gain an edge by examining video and watching hitters in the box. He admits this may be time to take another look to see if the information can help him breakaway from tendencies that opponents have picked up over the years.

“That might help me with tendencies and why certain guys are taking certain swings of certain counts. I feel like it is human nature to get into a tendency to get into a pattern. Especially if something is working, you are going to stick with it. It would be interesting to find out if there was something I could change.”