On Mark Trumbo, walk rates, swing rates and sustainability

It seems like it was eons ago now that the baseball world was scoffing at Mark Trumbo and his impressive home run totals because of his totally unimpressive on-base percentage.  Even with his mammoth power potential, his paltry 4.4% walk rate looked as if it might suffocate his career before it ever got started.  Comparisons to the likes of Mike Jacobs were being thrown around freely and unflatteringly.

But lo and behold, Trumbo did… something over the off-season and returned to the lineup a changed man.  A more patient man.  As of this writing, his walk rate stands at a perfectly acceptable 6.9% and his on-base percentage at a very nice .346.  No longer is he considered a one-trick pony but rather a middle of the order workhorse.  Of course, you knew this already.  You’ve been watching the Angels all season long and seen his transformation at the plate.  Back in April and May you probably also read analytical pieces about his newfound patience, but all of those pieces left off with the one glaring question of whether or not his improved plate discipline was sustainable.

Well, its August now and I’m here to tell you it is sustainable, probably.  Swing rates stabilize very quickly, but with Trumbo only owning 169 plate appearances through May, those early studies of Trumbo didn’t quite have a big enough sample size to draw upon.  Now though, Trumbo has 420+ plate appearances, which is still small in the grand scheme of things, but good enough given what is known about swing rates.  While his 2012 season walk rate looks respectable unto itself, it is still hard to judge it as just one stand alone number, especially since it was his big spike in walks in April that sparked this debate about Trumbo in the first place.

Good news, Trumbo’s walk rate is still much improved on a consistent basis this season.  Even his worst month of 4.5% is still better than his 4.4% rate for all of his rookie season.  It isn’t great news though since he hasn’t come close to matching that shiny 9.8% rate from August.  Nonetheless, it is an improvement and one that looks like it will stick.

Or so we hope.  There is still some cause for concern.  The real driving force behind his improvement in walk rate is that he stopped swinging at any and every pitch within two feet of the plate.  His overall swing rate is down three percentage points from last season and his out-of-zone swing rate is down nearly four and a half percentage points.  That’s the real benefit for Trumbo.  He is no longer getting himself out by swinging at bad pitches; the increase in walks is just a happy side effect.  Logic dictates that as long as Trumbo maintains that discipline, he’ll be fine.  Of course, that is much easier to do when you are going well, which Trumbo has been pretty much all season long.  Or at least he was right up until August.

This month could be a true trial by fire for Trumbo’s improved approach at the plate.  For the first time all season, he’s in a prolonged slump, carrying a .524 OPS so far in August.  If ever there was going to be a time where Mark was going to revert to his old bad habits, it is now.  If he allows that frustration to set in and starts getting desperate to make something happen that he just starts swinging away again, then he could well undo all the hard work he did the first four months of the season.  And thus far, it certainly seems that is the case with Trumbo upping his swing rate for August to 62.7% overall and 61.2% out of the zone.

In the immortal words of Scooby-Doo, “ruh roh!”  That isn’t disciplined, that isn’t disciplined at all.  If that was his swing rate over a full season, it would be the highest rate in the league both overall and out-of-zone by a pretty significant margin.  As ominous as this looks, it isn’t necessarily the death knell of Trumbo’s season.  Even by swing rate standards, this is a pretty small sample we are dealing with.  Who knows, maybe his recent day off will allow him to clear his head and get back to doing what permitted him to have this breakout season.  Or maybe he’ll just keep swinging and swinging and swinging until he erases all of that progress.