Vladimir Guerrero’s Lack of Power by Jack Moore April 27, 2010 [Statistics presented are prior to last night’s game] Rangers fans are likely quite happy with their new DH’s production through his first 17 games. Vladimir Guerrero has posted a .409 wOBA in his first 73 plate appearances as a Texas Ranger, largely on the strength of a .364 batting average. Guerrero has only hit 2 home runs this year, a mark well below his career rate of one home run per 19 plate appearances and his 8.0% HR/FB rate is the lowest of his career. This is continuing a concerning loss of power from last season. This is summed up quite succinctly by the following graph: In his most productive years – including the 23 wins he compiled from 2002-2005, the first 4 years of the Win Value era – Vlad’s ISOs were over 100 points above the league average. His prolific power was mostly supported by the ability to consistently blast home runs. We only have HR/FB data from 2002 on, but in those first 4 seasons, Guerrero’s HR/FB rate was above 17% for all of them and even above 20% for the 2002 and 2003 seasons, well above the league average rate of 11.5%. In 2009, his ISO plummeted to .164 and his HR/FB rate dove to 11.5%, both career lows. As a result, Guerrero posted a career low 110 wRC+, and given his position as DH, a career low WAR of 0.8. The projection systems all foresaw a rebound to 2008 levels of hitting produciton – .303/.365/.521 and a 130 wRC+. However, Guerrero turned 35 over the offseason, and a drop in power could certainly be caused by old age – especially given the beating his knees took on the turf of Olympic Stadium in Montreal from 1996 to 2003. Guerrero’s 7.6% strikeout percentage is what is currently keeping his batting line so high. Given his career strikeout rate of 12.4% (14.4% the last two years) and the fact that his O-Swing% has risen to over 50% – nearly double the league average – it is unlikely that this rate stays so low. That combined with likely BABIP regression will bring Guerrero’s line rapidly down to earth. Even though Guerrero’s season has started excellently, don’t be surprised if 2009 Vlad rears its ugly head in the upcoming months.