I'm in agreement w/ Griz. With the current shape of our bullpen, what current alternative do we have that could be as beneficial as Paxton throwing heat in the late innings? Hultzen's downward spiral has made me wary of pushing too hard on pitchers who demonstrate repeated physical infirmity.
A once-blown but rebuilt engine often will have a hidden weakness that won't be seen until the block cracks. I know some of Paxton's history has been akin to car-door dings suffered in a busy parking lot. But my gut tells me that he'll suffer a thrown rod if revved up too high over too long a period of time. He's better built for the quarter mile, but not the Indy 500. Perhaps pen-work is the best way to maximize his talent and not destroy his engine -- with frequent cool-downs, oil changes, and the occasional can of sea-foam for good measure.
Additionally, after seeing Karns' last start -- he looks like a good bet to do well. No rust, solid suspension, late model, low miles, nice torque off the line -- and the re-sale value ain't bad either.