Mariners Analysis: The Numbers Behind Nelson Cruz


Nelson Cruz is 34 years old and has been playing in the big leagues since 2005, when he received a 7 plate appearance cup of coffee with the Milwaukee Brewers. In those 7 plate appearances, he hit zero homeruns.  Since that time, he’s amassed a total of 3918 plate appearances and bashed a total of 205 homeruns.  Nelson Cruz developed his boomstick.

His power took a little while to develop.  That’s not surprising, it generally takes players time to develop major league batting power.  It wasn’t until 2009 that the Nelson Cruz that we know appeared in the batters box.  From 2005 to 2008 Cruz hit 22 homeruns.  In 2009 he hit 33.

What was it that changed for him.  Two things.  Flyball rate and HR/FB rate.  Flyball rate is simply the percentage of balls in play that are flyballs. HR/FB rate is the percentage of flyballs that go for a homerun.  Pretty simple.

Over his career he’s been a flyball hitter at a rate of 43%, and his career HR/FB rate is 17.6%.  This year, in his torrid start, Nelson Cruz has a flyball rate of 60.4% and a HR/FB rate of 27.6%.  That is a substantial difference in both of those numbers.  His previous yearly high in flyball rate was back in 2007 when, over 333 plate appearances, he managed a rate of 46.3%.  His yearly high in HR/FB rate came in 2013 when 21.3% of his flyballs went for homeruns.

So even if we compare his career yearly highs of 46.3% FB rate and 21.3% HR/FB rate, that’s still a difference of 14.1% and 6.3% respectively.

Numbers are fine, but what do they tell us.  Well, the HR/FB could well be close to sustainable.  Nelson Cruz is a big strong man and his power is not in question.  But the flyball rate?  There I’m not so sure he can keep things up.

More from Mariners News

The highest season flyball rate that we have records for belongs to Frank Thomas during the 2006 season.  Frank hit flyballs at a 57.3% clip that year.  In fact, the second highest mark also belong to Mr. Thomas for his 2002 season when 56.9% of his balls in play were in the air.  Nelson Cruz’s numbers don’t put him anywhere near those marks.  And so it’s reasonable to assume that his flyball number will come down a touch and end up somewhere around his career mark.

So by all means enjoy the homer show that Cruz is putting on at the moment, I know I am.  But don’t be too surprised when the homers stop coming with such astounding frequency.

Next: Mariners Sign Veteran Carlos Quentin to Minor League Deal

More from SoDo Mojo