Some news out of Pittsburgh tonight was that the Pirates have designated Zach Duke for assignment. He made $4.3M last season and is arbitration-eligible for the final time this offseason, so you can expect him to get something north of $5M. Whether another teams claims him or not remains to be seen, but he should be a decent, cheap option for a team looking for a back of the rotation arm.
No, Duke isn't going to 'wow' you with anything. Hes a left-handed pitcher whose average fastball velocity last season was 87.3 mph, and hes not going to miss many bats (career 4.71 K/9). However, he does 2 things pretty well that gives him some value: he throws strikes (career 2.45 BB/9) and he gets a solid amount of groundballs (career 48.9 GB%), which in turn lets him keep the ball in the park (career 0.94 HR/9). Duke uncharacteristically struggled last season with the longball (1.42 HR/9), which unsurprisingly led to a 4.95 FIP. His xFIP was a more appropriate 4.48, indicating he had poor luck with the homeruns, which makes sense considering his rather solid 48% groundball rate.
While Duke has never been a big strikeout guy, it is worth noting his strikeouts (using K/9) have been going up since 2007: 3.44, 4.23, 4.48, to 5.43 in 2010. His walk rate jumped up to 2.89 last season, but I think its safe to assume that he'll maintain a typical strong walk rate next year. Put it all together -- a return to normal levels in homeruns yielded with Duke's usual strikeout and walk rates, and you have a pitcher that likely resembles the +2.5 WAR starter he was in 2009, which is a nice little bargain for a $5M+ price tag, and an even better one if he goes unclaimed and signs for less. In his worst case scenario, I can see his FIP settling in at the mid to upper-4's range, but that still should be valuable enough to make him worth between +1 and +2 wins over a full season. For the teams that don't want to pay up for the services of comparable starters like Jeff Francis or Jon Garland, Duke represents a nice option to turn to.