Xavier Cedeno improved by simplifying his approach

The Tampa Bay Rays acquired LHP Xavier Cedeno on April 27, 2015 from the Dodgers for cash considerations after a slew of injuries necessitated a trade for a lefty reliever. Despite not having a ton of success at the major league level, the Rays saw something between the lines. Something they thought Jim Hickey could fix. Cedeno enjoyed a breakout season last year, posting a 2.35 ERA, 3.26 FIP and 3.16 xFIP over 46.0 innings pitched.

Though the overall season numbers are very good, his past splits are considerable and should be noted. Cedeno is automatic vs lefties, but he was known to struggle vs right-handed hitters before coming to the Rays. Looking at the data, it appears as though Jim Hickey had Cedeno ditch the four-seam fastball to simplify his approach and maybe clean up command of his other pitches. His splits and overall effectiveness immediately improved. Here's the data:

*Although pitch usage from Cedeno's lone October outing was not included, he did not throw a single four seam fastball.

Here is that same usage data in graphical form:

We see that, month by month, Xavier Cedeno cut ties with the four-seam fastball and moved towards a two pitch approach. For those of you who like to see the pitches themselves, here are movement graphs from Texas Leaguers. Ignore the pitch-type legend (which is the MLBAM classifications) and just focus on the movement. We've circled the different pitch types. Here are the first three months of the season.

And here are the last three:

His peripherals improved along the way, as shown in the decreasing (improving) FIP and xFIP over the season. And even though Cedeno was seen as a LOOGY to many, he consistently pitched against lefties and righties equally throughout the season. Of his 189 batters faced in 2015, 86 were righties. The consistent appearances vs them is displayed here:

*Small sample size note: October included all of one inning.

Xavier Cedeno continued to improve throughout the season even while pitching consistently to his weak split side. It looks as though the excellent Cedeno we saw in the 2nd half of 2015 could be the real deal, made possible by the extraordinary coaching of Jim Hickey. Look at just how drastically effective the change was:

Of course the sample size with Cedeno is small, but bear in mind that it does conform to what we would expect based on our broader understanding of pitch types. Both cutters and curve balls are generally considered to be more platoon-neutral than four-seam and two-seam fastballs, so an increased focus on those two probably does help Cedeno against right-handed hitting.

And if the simplified approach also brings with it better command overall, that's a clear win.

This is extremely encouraging. If Cedeno is anything like the pitcher he was in the 2nd half of last year, the Rays will have a real weapon in their bullpen that is probably being underestimated. Projection systems like Steamer and ZiPS don't believe the breakouts are sustainable. They project for him to perform slightly worse than his overall 2015 statistics, while I would like to believe in his adjustments and in the extraordinary powers of Jim Hickey.