Graphs & Breakouts: Studying Yusniel Diaz and Mark Vientos

Over the last several weeks I’ve spent time, and I mean time, playing around with Minor Graphs. Any moment I’ve had to myself over the last few days has been spent scouring the MiLB hitter pool, looking for possible under-appreciated breakouts. There’s nothing perhaps more valuable in all formats than identifying the players who might double their ADP year over year. Here’s a pair of players I’ve been intrigued by for one reason or another. Not everyone I’ll discuss each week will be a clear breakout, but they’re all worth discussing. 

Has Yusniel Diaz broken out?

One of my favorite “graph scouts” I’ve come across is Orioles outfielder Yusniel Diaz. We can see with a series of different queries that Diaz’s profile improved and stabilized (for the most part) over the last two seasons. 

First take a look at his rolling wRC+ since the beginning of the Cal League season in 2017. Following a rough April to May cold streak that bled into June, Diaz caught fire for a month and half before seeing promotion to Double-A Tulsa. Once in Tulsa his numbers ticked down from his June to July hot streak, but still produced some quality results, particularly over the last 30 days. Over the course of 2018, even post trade to an extent, Diaz maintained a very high level of offensive production. Sitting between a wRC+ of 120-150 from April to late July. Following the trade Diaz’s production dipped, before finishing strong.

Diaz wRC+.png

One of the more valuable elements of Smada’s brain child is the ability to line up a bunch of different metrics to specific production, and in Diaz’s case it’s easy to spot.

First the quality of his contact improved. His jump in line drive rate coincides with the increase in production.

Diaz LD%.png

He also stopped being so opposite-field heavy and began to pull the ball more.

Finally, the approach improved tremendously, as he began to walk more, and strikeout less, while tapping into more power.

To me it looks like it’s safe to say Diaz has made strides as a hitter. And at age 22 for the entity of 2019 he has a likely assignment to Triple-A Norfolk out of camp and some projected time in the bigs later in the summer. You buying?

Mark Vientos Sneaky Stud?

Yesterday on Twitter someone tasked me with identify the “next Alex Kirilloff” I suppose those translates to “The next guy about to blow up, that industry doesn’t discuss enough.” I suppose there are parallels between the two, but they’re underrated for very different reasons. Then again, the very nature of this post sort of flips that comp on its head with the whole Vientos not missing the entire season following his draft year “a la Kirilloff.” So why is Vientos here and why is he getting the full hyperbole bath from yours truly? Well, look at the jump in his overall production throughout his short season 2018 campaign. Something clicked for Vientos, and he become one of the better hitters in the Appy League. You can clearly see below something clicks in mid to late July and his overall production really ticks up.

Click on graph to toggle through all discussed metrics.

He began to put the ball in the air with more frequency, and his fly balls went further. The dip in flies directly relates to an overall decrease in his ground balls. So clearly Vientos adjusted his batted ball profile. The real kicker was his ability to do all this while increasing his walks, and maintaining his already very low K rate. Could this have been just a good month or so? Perhaps, but there’s enough underlying data for me to buy into a step forward from a young hitter with pedigree.

Overall, this is a profile to watch out for.