Which relievers could be on the move?

Francisco Rodriguez's recent success has some believing he could be traded in the near future. Jeff Hanisch/US Presswire

BOSTON -- The Farmers' Almanac weather forecast might be more reliable than a guesstimate on how relief pitchers will fare. The Boston Red Sox added Eric Gagne at the deadline in 2007, when his ERA was 2.16, and within a few weeks he appeared to develop a case of the yips. He allowed 17 runs in his 25 innings with the Red Sox, another way of saying they didn't get their money's worth.

Reliever Heathcliff Slocumb had a 4.13 ERA for the Mariners after joining them in a deadline deal -- after Seattle surrendered Jason Varitek and Derek Lowe for him, in what turned out to be one of the most one-sided swaps in history.

Bullpen investments are frightening for general managers. In an era in which a six-inning outing is considered good work by a starting pitcher, there are almost always outs to be accounted for at the back end of each game, and no good team wins without good work from its relievers. You have to have it.

But most relievers work like tides, with their flows and ebbs, and teams will try to catch them when they're on the rise.