Every year during spring training, there are a few unheralded players that make you sit up and take notice. This year, Tim Mayza is one of those players. The 6’ 3” left-handed pitcher, drafted by the Toronto Blue Jays in the 12th round of the 2013 draft, has had an unspectacular start to his career. Casual fans would be forgiven for not being aware of his first 25 years of existence. However, it seems that sometime last year he made some major strides, and those have combined with the Blue Jays’ lack of bullpen depth to put Mayza on the verge of a Major League call up.

As spring training wraps up, the Jays are probably slated to take two lefties back up north with them: J.P. Howell and Aaron Loup. The remaining left-handed pitchers on the 40-man roster include Mayza, Matt Dermody, and Ryan Boruki. This puts Mayza in quite an enviable position, as given Aaron Loup’s struggles the past couple of years (and the general unreliability of relievers), it’s likely that Mayza will get his first call up sometime this year.

So what makes Mayza so intriguing? Well, he’s a big left-handed power pitcher, a sought-after commodity in baseball. The success of the Kansas City Royals’ bullpen in 2014 and 2015, as well as individual pitchers like Andrew Miller and Aroldis Chapman, have made “super ‘pens” popular, where you have multiple stellar relievers with the ability to come in and shorten the game. This strategy looks especially good after the 2016 playoffs, where pitchers like Miller, Chapman and Kenley Jansen came in and threw multiple shut-down innings on several occasions. Great relievers today are almost as coveted as quality starters.

Mayza has the potential to turn into one of those relievers. During the Arizona Fall League last year, his average fastball velocity was 94.81 mph. He’s primarily a fastball/slider pitcher — he threw his fastball 76.32% and slider 23.68% of the time. Although this is an incredibly small sample size, it does give us some insight into his pitch mix and selection. Let’s take a look at his numbers since he got drafted.

Tim Mayza’s career stats Year Level IP K% BB% BABIP ERA FIP DRA Year Level IP K% BB% BABIP ERA FIP DRA 2013 Rookie 7.0 30.3% 6.1% .524 10.29 1.46 2.43 2013 Rookie 22.0 16.0% 9.4% .368 6.95 4.57 6.20 2014 A- 20.0 16.5% 11.7% .414 6.75 5.51 8.20 2014 Rookie 6.2 10.0% 14.3% .350 6.75 4.92 5.83 2015 A 55.2 26.3% 114.4% .333 3.07 2.62 2.88 2016 A+ 48.2 26.1% 7.5% .267 1.66 2.31 2.53 2016 AA 15.1 17.3% 20.0% .348 4.11 4.60 8.58 2016 AFL 14.2 23.1% 12.3% .342 6.14 4.25 N/A

Right off the bat, we can see that Mayza has trouble with his control. Although he strikes out a lot of batters, he walks a ton of batters as well. Last year, however, it seemed that he started to put it all together, reducing his walk totals while continuing to consistently strike out batters. In fact, he also posted a 56% GB rate at A+, the level at which he spent most of his 2016.

In addition, we also have some PitchF/X data available on him from his stint in the Arizona Fall League. Vertical movement on his four-seamer was 9.41 inches, while for his slider, it was -0.04 inches. So how does this compare to similar pitchers at the MLB level?

In the following table, I isolated those left-handed pitchers from the last three seasons who threw a fastball/slider combo over 90% of the time.

LHP with FB/SL combo Name FB% FBv FB VMov (in) SL% SLv SL VMov (in) Name FB% FBv FB VMov (in) SL% SLv SL VMov (in) Zach Britton 91.4% 95.7 5.6 8.7% 82.9 -2.9 Andrew Miller 47.3% 94.2 8.7 52.7% 83.9 -1.8 Glen Perkins 72.1% 93.5 10.2 27.9% 82.7 -0.4 Dan Jennings 59.6% 91.8 5.4 40.4% 83.6 -2.1 Oliver Perez 59.6% 91.6 8.7 40.4% 79.1 0.3 Boone Logan 50.1% 92.7 8.7 49.7% 82.5 1.5 Mike Dunn 60.7% 94.4 10.7 38.7% 87.3 1.9 Jake Diekman 72.0% 96.3 6.8 26.4% 84.6 1.4 Sean Doolittle 88.6% 94.0 11.7 8.6% 81.3 0.5 Antonio Bastardo 67.6% 91.9 12.3 27.9% 83.4 4.1 Aroldis Chapman 75.3% 100.0 10.8 18.8% 87.9 3.7 Jake McGee 91.6% 94.9 10.6 2.2% 81.4 3.6 Marc Rzepczynski 57.9% 91.5 6.8 35.3% 84.1 -2.5

It seems that there are legitimate reasons for the Blue Jays to be excited about Mayza. He generates an above-average swing rate on his fastball, and according to Brooks Baseball, his slider has 12-6 depth and he throws it at a good velocity.

However, as with all prospects, this optimism must come with caveats. Mayza may have the velocity and quality pitches to succeed at the the major league level, but he doesn’t have a track record of success, and will need to continue to improve. Steamer projects him for a subpar 4.78 ERA and a 5.01 FIP.

Mayza’s velocity will always make him a tantalizing prospect. Of the 645 relief pitchers who threw at least 10 innings in relief from 2014 to 2016, only 97 (15%) pitchers threw harder than Mayza’s 94.8 mph. If you narrow to the 163 pitchers who were able to stick around to throw at least 100 innings over those 3 years, that number drops to 32.

It would be great for both Mayza and the Blue Jays if he continues to make strides in his performance. If he continues to improve his BB rate, and can maintain his excellent GB and K rates, he could be knocking on the doors to the big leagues very soon.