Breaking down the regression of Julio Rodríguez and Eugenio Suárez with Tanner Stokey of Driveline Baseball

Tanner Stokey, Director of Hitting at Driveline, stops by to explain the regression of two of Seattle's biggest sluggers.

(Ron Schwane/Associated Press)

It is no secret the Mariners haven’t gotten the production they have desperately needed from a few key players in the lineup. Regression was a word that was tossed around the Seattle fanbase often this offseason, but it has hit this team hard as we stand here in late June.

The two main culprits of this regression are also huge parts of the DNA of this team, Julio Rodríguez, and Eugenio Suárez. Both players have seen big dips in production, which got me wondering what the issue could be. A frustrating lack of consistency and a power outage has been the story of their season, leaving us searching for answers.

By both my eye test and the data, both players have struggled to hit the fastball this season. Struggling to hit the four-seam fastball is a major issue, and anybody who has been around the game for a long time knows you have to hit the fastball before you can do much else at the plate.

To find more answers I checked in with Tanner Stokey of Driveline Baseball. Tanner and the Driveline hitting team collect data on every hitter and analyze them using several metrics that they use to help train their hitters. J.P. Crawford trained at the Kent facility this offseason, working with Stokey and his team.

What we found was very interesting, a pattern of statistics that tell the story of these two hitters in 2023.

Julio Rodríguez

We can see here that the 22-year-old centerfielder scores in a very similar fashion in most of Driveline’s metrics, including his bat speed, bat-to-ball, and swing decision data. These are all very important and it is encouraging to see that he has maintained all of the bat speed and exit velocity data of his dominant 2022 season.

The highlighted number under the category AA indicates a decreased attack angle this season for Julio. Attack Angle measures the angle that the barrel takes through impact with the baseball. A hitter would want this to be positive to match the negative plane of the incoming pitch.

Rodríguez’s attack angle is down almost nearly 3 notches this season, meaning he is swinging more downward than last season. His groundball rates are up this year as well, and his BABIP is 47 points lower.

While his attack angle is certainly much lower this season, the young slugger has raised his launch angle significantly this season on four-seamers. Having a higher launch angle is generally thought of as a good thing, but not in this case.