I was kicking around drafting a post on impending free agent Jeremy Affeldt based on his surprisingly good numbers this year (in a hitter's park), but Fangraphs beat me to it. Affeldt added a couple miles per hour to his fastball and curve, which resulted in a jump in his strikeout rate and drop in his walk rate without affecting his high groundball rate.
While his past struggles might keep the price down, hard throwing lefty relievers who can get righties out tend to do well on the free agent market, so he will not come dirt cheap. But paying a high-leverage reliever mid-leverage reliever money could make for a nice bargain. Relief pitching is obviously not an immediate priority for the Royals, but if the Royals are not going to spend big elsewhere, this is the type of moderate deal that makes the team better without breaking the budget. Plus, adding bullpen depth would allow the Royals to move a reliever for help in a different area of need (which the free agent market likely overvalues).