I’ve encountered a few Mariner fans recently that view Yuniesky Betancourt a changed man since Jose Castro took over as the team’s hitting coach back in June.  They are so encouraged by the progress they’ve seen that they no longer resent Yuni like many of us do, and think that he can finally begin living up to the “shortstop of the future” tag that was inappropriately placed on him upon his arrival in 2005.  “Yuni finally has a hitting coach he can trust,” they might say.  “They’re both Cuban born shortstops!”

Such a sentiment is complete lunacy.

Yuni put up a vital line of .279/.289/.405 over the first 70 games of the season under the tutelage of hitting coaches Jeff Pentland and Lee Elia.  In the 74 games since Castro arrived on the scene Yuni has put up a line of .261/.290/.348.  What improvement?

Of course, the big change in Betancourt that people are seeing is his new found plate discipline.  Before Castro came along Yuni was walking in just 1.5% of his plate appearances.  Since Castro started working with Yuni he’s been walking in 3.7% of his at bats.  What a transformation!  I’d hate the break it to you, but that 3.7% is still significantly lower than anyone else on a team of free swingers and the 2.2% improvement isn’t anything to get excited about. 

Not only is it something not to get excited about, but it could actually be a cause for concern.  While I love walks and players that draw a lot of them, Yuni’s new approach seems to be hindering his ability to hit the ball hard and get hits. 

His drop in batting average and slugging percentage since Castro has taken over could be evidence enough, but upon further investigation I’ve found that Yuni’s hitting fly balls 48.5% of the time since Castro took over, which is a huge jump from the 33.3% pre-Castro and his career marks.  Unless you’re a big time power hitter with a propensity for hitting balls over the fence, fly balls aren’t good and are much more likely to be turned into outs compared to line drives or ground balls.  Yuni’s sailing fly ball rate has caused his line drive rate to dip slightly from 18.9% to 17.8% and his ground ball rate to plunge from 41.5% to 33.9%, which is all bad news.  

Additional evidence: Yuni was already hurting the team offensively before Castro arrived, posting a -1.13 WPA (Win Probability Added) in those first 70 games.  Since Castro came aboard it’s dipped to an even worse -2.18.  (For comparison, the best hitters in baseball have WPAs around 5 and 6.  Raul Ibanez’s is at 2.48.)

The point of this post isn’t to bash Jose Castro; I’m just trying to issue a warning to those of you jumping back on the Yuniesky Betancourt bandwagon.  He’s shown an insignificant amount of improvement in one of his problem areas that has apparently effected him negitively in other areas and– as of right now– he’s not a better player because of it.

Now, if Yuni’s batted ball percentages begin drifting back to normal and he continues to work on his plate discipline, then he will be a better player thanks to Castro.  It’s very possible and will be something to watch for, but I remain skeptical until then.