Joe Nathan wants his fastball back, but he's going to have go back to basics to find it. Working his way back from ligament reconstruction surgery performed 14 months ago, Nathan is headed to the disabled list because of a tender elbow. A magnetic resonance imaging taken Saturday revealed inflammation in the elbow and was sent to the doctor who performed Nathan's surgery, Dr. David Altchek. "We just want to make sure there is nothing we might have missed," manager Ron Gardenhire said. "That's the next step. It's the right thing to do." Nathan said his recovery had reached a standstill. In fact, he added, pitching in games probably was being impeding it because what's really holding him back is that he can't extend his elbow enough to make his fastball as effective. The fastball was his primary pitch when Nathan was compiling all but three of his 246 saves for the Twins, which rank second to Rick Aguilera's 254. "I need to get back to what worked so well for me then, using more fastballs," Nathan said. "I need to get my extension where it needs to be. I feel like since Day 1, I've been competing and just trying to put up zeros, any way I could....So I've been throwing a lot of breaking balls, a lot of curveballs. "That's not really going to help me with my extension. It's almost, in fact, hindering me from getting my extension when I throw fastballs."