According to Fangraphs, the average fourseam fastball velocity was 92.0 MPH in 2013, and the average changeup velocity was 82.9 MPH. Well, two flawless appearances into 2014, Trevor Rosenthal has done a tremendous job at making these two MLB-average velocities look like they belong to mere minor leaguers. Of his 25 pitches thrown, 22 have been fourseam fastballs and three have been changeups with average velocities of 97.47 MPH and 88.41 MPH, respectively.
I realize 25 pitches isn't enough to get a true gauge on a pitcher, but both velocities are almost identical to Rosenthal's career averages. This means his fourseam fastball is nearly 5.5 MPH faster than last year's league average, and his changeup is less than four MPH slower than the league's average fastball. Yep, you read that correctly. Let's take this to another level and make some visual comparisons:
Whoa. All right, none of the seven pitchers on the graph are necessarily classified as fourseam fastball pitchers. I get that. However, all seven have been able to have success (some temporary, some sustained) in the major leagues with a fastball velocity that is oh so similar to Rosenthal's changeup. Yes, a vital piece of information is that Rosenthal is a reliever and has a "fresher" arm for the duration of his appearances, but I honestly don't think his changeup velocity would be much different were he a starter. Plus, I have already made my opinion known on what Rosenthal's role should be on this team.
His performance against the Reds:
Rosenthal garnered two saves over 2.1 innings pitched in the series and faced just seven hitters in the process: Zack Cozart (four-pitch strikeout), Brayan Pena (four-pitch strikeout), Roger Bernadina (five-pitch flyout), Brandon Phillips (five-pitch strikeout), Joey Votto (two-pitch flyout), Jay Bruce (two-pitch groundout), and Todd Frazier (three-pitch flyout).
Votto is obviously the class of the Reds lineup, so let's look at his plate appearance in particular. He is a career .341 hitter with 42% of his 157 career home runs coming against fourseam fastballs. His career slugging percentage on fastballs in the general area of last night's flyout is a whopping .843. Thus, two possible hypotheses can be made from this extremely small sample size (one plate appearance): 1) Votto just barely missed barrelling the pitch or 2) Rosenthal's fastball is not normal/borderline superhuman. I don't know about you, but I will take the latter.
Of the seven plate appearances in the series, one clearly stands out from the rest. In fact, I could make a substantial argument behind it being the best plate appearance of Rosenthal's young pitching career (407 career PAs). I realize it came against Brayan Pena (a career .256 hitter), but that shouldn't detract from the fact that Rosenthal was absolutely unfair in both pitch selection and pitch execution:
Honestly, this graph only tells half of the story. The fact that Rosenthal went from ~98 MPH to ~88 MPH to ~98 MPH to ~88 MPH is already unfair on the hitter. Well, he went one step further by changing Pena's eye level on each pitch—going up-down-up-down.
So, what can make Rosenthal even more effective going forward?
I am a fastball-changeup guy. If you read any of my old blog before I joined Viva El Birdos, then this should be nothing new to you. This is the main reason why I became infatuated with Michael Wacha last season. There is just something about making a hitter look foolish on a relatively straight pitch that gets me all warm and fuzzy inside. Well, right now Rosenthal throws his changeup 10-15% of the time. If he is able to ramp that up to 20-25% and gain comfort in using it in any count, he realistically could have an ERA in the low 1.00's this season.
Need some more convincing? Then I leave you with this:
If Rosenthal can develop a consistent changeup like the one seen in this .gif, he will somehow become even more fun to watch and more importantly, even more unhittable.