The Blue Jays Stuff Report – All Star Break Edition

The Blue Jays Stuff Report will be appearing in this space every two weeks. The metric was created by Dr. Mike Sonne, who has a PhD in biomechanics from McMaster University. For his work on pitcher fatigue, injury, and other baseball related research, please visit his website over at

Stuff Report Volume 1

Stuff Report Volume 2

Stuff Report Volume 3

Stuff Report Volume 4

Stuff Report Volume 5

Stuff Report Volume 6

Time to kick back our feet, relax and enjoy the All-Star break. Anyone curious as to how Stro’s mountie pants are going to influence his Stuff in the second half of the season? To be determined…


Seriously. Stroman is a fashionable mountie. Does no one else see this??

Blue Jays Starters

v7-SP Table

v7-SP graph

The Stuff metric was designed as a tool to evaluate performance of pitchers – and this means looking at how good their stuff is¬†compared to one another, but also, to look at how a pitcher changes over the course of the season. There are a couple very interesting examples with respect to the change in Stuff by one pitcher over time that I’d like to talk about. The first one is Marcus Stroman. His struggles have been well documented, and of great concern to Blue Jay fans. I think everyone would agree though – Stroman has been coming back around in the past couple of weeks, starting with his White Sox start (which fell apart), and then two great starts against the Clevelands and Kansas City. His stuff has gradually improved in the past four weeks, and now it’s as close to 2015 levels as it has been since the first month of the season. Looking into this a bit more closely, it appears that Stroman has raised his FB and breaking pitch velocity during that time (the low part at week 92 and 79 mph, to 93 and 85 mph). I’m sure there will be other bumps in the road, but Marcus appears to have adjusted back to take control against hitters.

The other example is AL All Star, Marco Estrada. Marco was described as “a right handed Mark Beurhle” at the Pitch Talks event here in Hamilton last week, and look at his stuff, you can see why. He relies on pitching, and not pure stuff to win against hitters. That being said, Marco has hit a few bumps in the road recently, and his reported back pain has gotten worse. Since the end of May, Marco has lost Stuff at an alarming rate – his fastball velocity has dropped from 88mph to 87 mph, and more importantly, his change in speed has dropped from 13% to 11%. It’s definitely for the best that he gets healthy and returns to his previous form, but it’s a shame to see someone who has worked so hard miss out on such a well deserved accolade, like the All Star Game.

Blue Jays Relievers

v7-RP Table

v7-RP graph

As the stuff metric is still in its infancy, it’s difficult to say what can become a red flag. A drop in Stuff can signify changes in velocity, which are useful indicators of injury – but rapid increases in stuff could also be measures of concern. Gavin Floyd saw a rapid increase in his Stuff right before hitting the DL. Drew Storen had a large drop in his Stuff, but he appears to have found his groove again and looks to be headed in the right direction.

One reliever to look at through a cautious lens is Roberto Osuna. While his Stuff still remains elite, it has been declining over the past few weeks. This comes from a 1.3 mph drop in FB velocity (compared to Volume 3). The All Star break comes at a good time for Roberto – but it will be interesting to monitor how things change when he returns from the break.

Related Articles

Leave a comment

Use your Baseball Prospectus username