The Brewers have to make arbitration decisions on two of their relievers, Todd Coffey and Carlos Villanueva. Each has enough service time to qualify for salary arbitration but not enough to become a free agent, so this is different from the arbitration decisions on players like Trevor Hoffman and Craig Counsell.
Coffey made $2.025 million last season and would likely see a bit of a raise, a safe estimate would be that he would be awarded something close to $3 million in arbitration this season. He put up two strong seasons with the Reds in 2005 and 2006, with a FIP around 4, followed by two weak years with the Reds. He was waived and acquired by the Brewers near the end of the 2008 season. In 2009 he threw 83 innings with the best strikeout to walk rates, FIP, and ERA of his career. He struck out even more batters in 2010, and put up a FIP somewhere closer to his career norm-- 4.20-- but saw his ERA jump up to 4.76.
Like usual, the projection for Coffey should lie somewhere in the middle of what he's done in the past. He's 30, but should be in line for a season with something around a 4.00-4.20 FIP and ERA. The high strikeout numbers last year are a positive, and Coffey has a track record of durability and can go multiple innings. I would likely offer him arbitration for these reasons. It's not impossible to find his level of production for something just slightly less on the free agent market or giving something up in a trade, but I don't think it's worth cutting ties with Coffey, who would probably be able to be given away on a $3 million contract to some team at least. If the team is making a push for a particular player and really needs $2 million, this could be one area they look for savings, but it seems unlikely that they would want to let go of a dependable pitcher in what will probably be a very young bullpen.
Carlos Villanueva is in a contract situation similar to Coffey's. He made about $1 million this year and would likely see his salary increase to about $2 million. Villanueva put up the best strikeout rate of his career-- an impressive 11.45 K/9 in 52 innings-- and ran up a 3.7 FIP. An unfortunate BABIP may have contributed to his 4.61 ERA. He was inexplicably buried on the depth chart under Ken Macha despite this yearlong performance that looked pretty solid overall. Villanueva has steadily improved his skills in his time in the majors but has never had a "breakout season".
I'd project him, as a full-time reliever, similarly to Coffey: 4.00-4.20 FIP and ERA. That, by nature, makes him worth a similar amount. If the Brewers see Villanueva's cost as about $2 million, they should offer him arbitration as well, again the argument goes that probably many teams would be willing to take him for the cost of just picking up his salary if he wasn't needed.
The Brewers are in a strange situation of having many cheap, capable bullpen arms, while having a severe shortage of starting pitchers, and it might seem that they could give a few away and still be fine. However, it's not a smart use of resources to just dump pitchers with positive value. Unless my estimates for salary awards are way off, I think it would be wise to offer both pitchers arbitration-- not necessarily because both will make the team or be necessary for success, but because they'll be worth what they will probably be paid and come with significant upside due to high strikeout rates. Who knows how tight money will be or what the main goals are, but in terms of pure value versus cost, both pitchers are worth what they are likely to be paid.