Fantasy Baseball: Buy or Sell Yandy Diaz’s Power Surge?

The Tampa Bay Rays acquired Yandy Diaz from the Indians prior to the 2019 season. Diaz hit for a solid .283 BA and .362 OBP during his time in Cleveland. However, a mere .366 slugging percentage completes his slash line during that period. As a member of the Indians, Diaz hit just one home run in 299 plate appearances. Is he an add for your Fantasy Baseball team?

It it is well documented that Tampa Bay’s management saw Yandy Diaz and his average exit velocity of 92.1 mph as an enticing stat – if he could just starting lifting the ball at a more advantageous rate. The Rays are looking pretty smart as the data appears to prove their hypothesis on Diaz correct. The 27 year-old Cuban born talent has hit 6 bombs in 22 games this season with a beautiful line of .289/.398/.579. Is he worth an add for your Fantasy Baseball team?

While he obviously won’t sustain those rates, the question still remains: should fantasy owners buy into his newfound power? Let’s look at some numbers from an admittedly small sample size. His 2019 statistics tell a story of superior plate discipline and power results seemingly unexplained by underlying stats.

Let’s start with Diaz’s plate discipline, a hit tool that has always been a strength. He has raised his BB rate from last season by over six percent in the early going. In 2019, he is walking at a rate of 15.5 %, sufficient for 19th best in the MLB. He has increased his K rate to 18.6%, but this still represents the 61st lowest strikeout rate. He is demonstrating his greatest BB/K rate of his career at .789.

So he continues to get on base better than most – but what is happening when he puts the ball in play and has his approach changed? If you asked Yandy that question, he might reply similarly to a question asked of him on April 7th, 2019, after he hit his 2nd home run of the season.

"“I’ve always had the power. The power has always been there. Now I’m just trying to elevate and get a little launch angle under it.”"

We we know that an increased launch angle is what Tampa has in mind when getting Diaz. He has seemingly confirmed this effort as well. His average launch angle in 2017 was literally 0 degrees. In 2018, he elevated it to 4.4 degrees. This season he has batted balls at an average launch angle of just 3.7 degrees, a decrease from last year. So it seems that while he’s making the effort to lift the ball more, he’s not having the success the organization envisioned.

Perhaps his exit velocity and hard hit rate could explain his newfound power. Not likely as his average exit velocity is down from last season, sitting at 90.7 mph, which still comes in at 76th in the league. Naturally, his hard hit rate is also down, registering in at 140th with a 39.1 %.

Yandy has already produced more barrels, 5 so far, than in each of the past two seasons in the major leagues. Accordingly, his barrel rate is up to 7.8 % as compared to 4.4 % in 2018. That still just qualifies for an above average, if underwhelming, 144th best barrel rate. Perhaps that modest improvement could explain why a couple more of his batted balls have left the park or hit a gap this season. Nothing can be discounted with data from less than 70 batted balls – but again, not likely.

Diaz’s expected BA is just .249 compared to his actual .277 average, while he is slugging .542 but has an expected .405 slugging rate. This suggests that his slugging percentage will come down unless his efforts to increase launch angle materialize – and they certainly could. He remains a solid candidate to keep up his Average though as he is a career .282 hitter.

It looks like Yandy has benefitted from some luck on his batted balls. A few have cleared the fence in the young season. However, with his current hard hit rate, barrel rate, and launch angle, we can expect that his batted balls will result in a decreased percentage of extra base hits – certainly of home runs.

There is reason for optimism of favorable power numbers compared to 2017-2018 though. The first is that Yandy has been asked to hit in multiple spots, from leadoff to cleanup and most recently 3rd. These lineup spots traditionally come with differing expectations of a hitter’s goal. Cleanup hitters need to drive in runs, and leadoff hitters are asked to get on base at a high clip with power as a lower priority. It’s possible that Diaz has struggled to adjust to the newly preached launch angle approach while trying to do his job in the order.

The case of Yandy Diaz’s power game is a curious one. Tampa acquired him with increased power in mind, and he’s delivered. Yet his batted ball stats don’t convincingly support his power production. However, given that the Rays are emphasizing launch angle and Diaz has verbalized his efforts to this end, Diaz projects as a solid candidate to sustain these numbers despite few supportive underlying stats.