Just one more quick note on soon-to-be-newest Dodger reliever Matt Guerrier:
According to Baseball-Reference.com, Guerrier has had Wins Above Replacement values of 2.3 in 2009 (age 30 for most of the season) and 1.4 in 2010 (age 31). The Dodgers' expectation or hope in giving him a $12 million contract through 2013, presumably, is that he'll repeat that performance over the next three years.
But since 1990, again according to Baseball-Reference.com, only three relievers above age 30 have had as many as five seasons with WAR over 1.0 without striking out more than 7.0 batters per nine innings (Guerrier's career high). And none of those pitchers — David Weathers, Mike Timlin and Steve Reed — did so in more than three consecutive seasons.
In other words, what the Dodgers are asking Guerrier to do — be a productive reliever for a third, fourth and fifth season in a row after turning 30, without striking out many batters — has not been done by anyone in at least the past 20 years.
Update: To be precise, Jeff Reardon accomplished the feat from 1988-92. His first two seasons fell outside my original search. Dan Quisenberry (1983-87) and Kent Tekulve (1981-87) also succeeded. But that's it since at least 1970.