Relief pitchers are viewed by many as the most volatile assets in baseball.

That remains the case now, maybe more than ever before. And that is why relievers will again be among the most desired – and fickle – commodities at the trade deadline.

Consider the turnover among the game's top closers. Twelve relievers finished with 36 or more saves during the 2009 season. A majority of them are no longer closing: Joe Nathan, David Aardsma and Jonathan Broxton are on disabled lists; Brian Fuentes, Ryan Franklin and Fernando Rodney have been demoted; and Trevor Hoffman has retired.

As a result, some teams are entrusting less experienced relievers with key roles. Perhaps not coincidentally, big league bullpens combined to lose 250 games through Saturday – the highest total as of May 28 in the past decade, according to STATS LLC.

The decrease in offense across the majors has made for lower-scoring games and more save opportunities. In that sense, the value of a good, experienced bullpen has never been higher. Fans of the Giants, White Sox, Angels, Reds and Yankees were reminded of that on Saturday, when each of their teams suffered a walk-off defeat.

Fortunately, contenders could be looking at a buyer's market for bullpen help leading up to the July 31 non-waiver trade deadline. This is a much better year to be looking for a closer than an ace. While the likes of Heath Bell, Francisco Rodriguez and Matt Capps could be available, there doesn't appear to be a Cliff Lee comparable there for the taking.

Among the teams that should be in the market for bullpen help: the Texas Rangers, Boston Red Sox, Chicago White Sox, Detroit Tigers, Colorado Rockies, and Los Angeles Angels.