How Yandy Diaz became the best 1B in MLB

Tampa Bay Rays first baseman Yandy Diaz John Jones-USA TODAY Sports

How Yandy Diaz became the best first baseman in MLB

By Caleb Thomas | Last updated 5/18/23

First base is known as a bat-first position. Many of the top power bats in the league reside there due to the general size of those who play first base.

While Yandy Diaz has not always played first, with lots of time spend at third base, he took over the position for the Tampa Bay Rays in 2023. He has done it well, leading Major League Baseball in wins above replacement so far this year, according to Fangraphs.

Diaz has always been a solid player, but nobody has confused him for a superstar. From 2017 to 2022, he had an OPS of .782 with 39 homers. Although the numbers weren't bad, Diaz never seemed to tap into to the raw power he possesses. Until this year.

Yandy Díaz grand slam!

His 10 homers are already more than he had all of last season pic.twitter.com/TGISN40WUk
— Talkin’ Baseball (@TalkinBaseball_) May 13, 2023

Diaz's 10 bombs are tied for fourth among first basemen and he also carries the second highest on-base percentage in the position group. It's a combination that has been dangerous for opposing pitchers, but it's a huge outlier among his career stats. Is this for real?

Performance at this elite level probably isn't sustainable, but there are changes that suggest that this improvement is more than a hot streak. The 31-year-old has changed his plate approach this season, leading to a dramatic increase in average exit velocity.

The raw power has always been there -- throughout his career, Diaz's max exit velocity has been towards the top of the league, according to Baseball Savant. He just wasn't able to consistently hit the ball that hard.

Along with pulling the ball at a career-high percentage, Diaz has also started to hit the ball in the air much more, which has led to the increase in power. A great article by Fangraph's Jake Mailhot analyzed the change in Diaz's game and came to the conclusion that the stat boost is fueled by approach rather than swing.

Mailhot points out the stats when Diaz is behind, even or ahead in the count and they show that he tends to lift the ball much more when ahead in the count, even compared to previous years. It's a small change for Diaz, but one that has yielded excellent results.

Diaz is currently sidelined with an injury, but is day-to-day. The pieces are seemingly all coming together for the Rays as Wander Franco and Josh Lowe are having huge breakout seasons as well.

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