Mariners: Will Justin Dunn have a breakout season?

There is always a lot that can change during the offseason, and a few Mariners players looked different when they arrived in Arizona. One of those guys is the 25-year-old starting pitcher, Justin Dunn.

The young right-handed starter worked with a nutritionist to make dietary changes and lost 10 lbs during the offseason. In an interview, Justin said this is “arguably the best shape I’ve ever been in in my life.”

Going into the offseason, the former first-round selection knew he would need to compete and change some things because 2020 just wasn’t good enough. Dunn said,

"To say I was happy with last year would be doing me a disservice. When I had that exit interview, I had all of the stuff written down on my phone of what I was already planning on doing, and getting to work on in the offseason. That conversation also kind of lit a fire under me, put things into perspective and made me work a bit harder, but I was already going to head down that path anyway."

I love this quote. This is a testament to Justin Dunn’s competitive nature, drive, and work ethic. I don’t know if the Mariners intentionally added more pitchers to put pressure on guys like Dunn, but sometimes that’s what’s needed.

Justin Dunn’s pitching changes

During his first bullpen session of Spring Training, his fastball was averaging 93-95 mph. Yes, you are correct, Justin didn’t throw that hard last season.

According to Baseball Savant, Dunn’s 2020 fastball was 91.2 mph on average. Someone get me Justin Dunn’s diet and workout plan!

This is huge news for Justin. It’s not easy for pitchers to suddenly increase their velocity in less than half a year. Improved velocity is particularly important for Dunn because he mostly throws a straight fastball.

He does have a sinker, but he only threw it eight times in 2020. At this day and age, a 91.2 mph four-seam fastball isn’t very effective especially if your offspeed pitches are just as ineffective as your fastball (which is the case for Justin).

But, Justin Dunn has been working on a new changeup which is the type of news we want to be hearing. We saw how much better Justus Sheffield was after making some changes during Spring Training.

The New York native is apparently using a new grip inspired by Pedro Martinez, Frank Viola, and Trevor Hoffman… I think that’s a good idea. The Mariners pitcher also acknowledged that the AL West is lefty-heavy and an improved changeup could up his game by quite a bit.

When Justin threw his changeup last year (6.2% of the time), batters hit .375 off of it. His whiff percentage was just 14.3% and the put-away percentage was 5.9%. Oof.

Justin Dunn’s first Spring Training outing

Justin Dunn started against the Athletics yesterday and threw two scoreless innings. It was a good and bad outing for Dunn. He walked two batters and gave up a hit to load the bases. But his second inning was much smoother and finished the A’s batters in a 1-2-3 fashion.

Mariners fans should be excited for Justin Dunn

I know many Mariners fans had high expectations for Justin when he came over and he hasn’t been all that impressive. But from what I have seen so far in Spring Training, there is a lot telling me that Dunn will be different this year.

The Boston College product is highly motivated to get better and is doing everything within his power to improve. That’s the type of spirit we desire as fans, and I will one of his biggest fans this year.

For me, he is another breakout candidate for the 2021 season alongside Evan White. Dunn’s got the work ethic and he proved it this offseason. He looked good in his first live session last week so it will be interesting to see if it translates to live games against other opponents.