Duensing to the Rotation?

Overall, the Minnesota Twins’ starting rotation has been excellent — the team boasts a 4.01 xFIP from its starters, best in the AL. But, while Francisco Liriano is re-establishing himself as an ace and Carl Pavano is thriving on the power of the ‘stache, the rest of the rotation is unsettled at the moment. Scott Baker has been hampered by poor outfield D, but he’s dealing with elbow tendinitis. Kevin Slowey’s vanishing ground ball rate has contributed to a so-so-season. Nick Blackburn, meanwhile, has seen his K rate enter untenable territory.

As such, the Twins are considering moving Brian Duensing back into the starting rotation, likely at the expense of Blackburn. If Duensing does make the shift from the ‘pen, what’s his fantasy value? Let’s take a closer look at the 27-year-old lefty.

Duensing was selected out of Nebraska in the third round of the 2005 draft. A 5-foot-11, 195 pound Tommy John survivor, Duensing was drafted more for his polish and proximity to the majors than for his stuff — Baseball America said he sat 86-90 MPH with his fastball and possessed a solid changeup. BA also voiced concern about the Cornhusker’s durability, as he had to miss the Big 12 Conference tournament due to lingering elbow soreness.

After carving up less experienced hitters in Rookie ball that summer (50.1 IP, 9.8 K/9, 2.9 BB/9, 3.27 FIP), Duensing made his full-season debut in 2006. He jumped all the way from the Low-A Midwest League to the Double-A Eastern League, with a stop in the High-A Florida State league in between. In 160 combined innings, Duensing had 6.6 K/9, 2.2 BB/9, and 0.7 HR/9. According to Minor League Splits, his ground ball rate was 51.8% and his park-and-luck-adjusted FIP checked in at 3.87. After declining to include Duensing in its ’06 Prospect Handbook, BA rated him as the 18th-best talent in the Twins’ system prior to 2007. While noting that nothing in Duensing’s repertoire amazed scouts, BA claimed that “all his offerings — both two-and-four-seam fastballs that sit in the upper 80’s, a curveball, slider and circle changeup — grade out as average or a tick above at times.”

The next year, Duensing split the season between Double-A and the Triple-A International League, spending the majority of his time at the latter level. He whiffed 6.7 per nine innings, walked two per nine and gave up 0.8 HR/9 in 167.1 IP. Duensing got grounders 48.2% of the time while posting a 3.56 adjusted FIP. Baseball America bumped him up to eighth in Minnesota’s system, again lauding his four-pitch mix and quality control.

Duensing’s stock slipped a bit in 2008, as his strikeout rate took a tumble back at Rochester. He punched out five batters per nine innings, handing out 2.2 BB/9 and coughing up a homer per nine frames. Duensing continued to keep the ball down (51.7 GB%), but his adjusted FIP fell to 4.13. BA dropped him to number 16 on the Twins’ top 30 list, wondering if a move to relief might be in his future — Duensing reportedly sat 94 MPH with his fastball out of the ‘pen for the U.S. Olympic team in Beijing.

In 2009, Duensing divided his time between the Red Wings and the Twins. He had 5.3 K/9, 2.3 BB/9, 0.2 HR/9 and a 46.2 GB% in 75.1 minor league innings. Adjusting for that tiny homer rate, Duensing’s FIP was 3.89. As a Twinkie, Duensing made nine starts and 15 relief appearances. He posted a 4.42 xFIP in 52.2 IP as a rotation member (his actual ERA was 2.72), with 5.64 K/9, 2.56 BB/9 and a 46.3% ground ball rate. Duensing had 5.74 K/9, 4.6 BB/9, a 44.2 GB% and a 5.36 xFIP in 31.1 innings as a reliever. His pitch selection between to two roles wasn’t especially different (he incorporated his curve more as a starter), nor was his fastball velocity (90.5 MPH out of the ‘pen, 91.3 MPH as a starter).

This season, Duensing has pitched exclusively in relief. The surface results look spectacular — a 1.67 ERA in 43 innings. His peripherals, by contrast, aren’t so special. Duensing’s got 5.65 K/9, 2.51 BB/9, a 49.6 GB% and a 4.24 xFIP. That svelte ERA is due in large part to a .241 BABIP and a 91.1% rate of stranding runners on base.

For the rest of 2010, ZiPS projects 4.83 K/9, 3 BB/9, 1.17 HR/9 and a 4.73 FIP from Duensing. That forecast comes in a swing role, so his projected FIP would be higher solely as a starter. CHONE has a more optimistic projection — 4.92 K/9, 2.81 BB/9, 1.03 HR/9 and a 4.59 neutralized ERA as a full-time starting pitcher. That’s basically the extent of Duensing’s utility — he could be an average big league starter. There’s nothing wrong with that from the Twins’ standpoint, as a passable rotation arm yet to reach arbitration has value. But fantasy owners shouldn’t get overly giddy about Duensing.