Toronto Blue Jays’ Tim Mayza: How good are lefties with a 95mph fastball?


Jays From the Couch examines how special Toronto Blue Jays’ prospect, Tim Mayza, could be as a fireballing lefty


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What kind of reliever might the Jays have in Tim Mayza?  Wait, you don’t know who Tim Mayza is?  Well, I guess that’s fair.  Mayza was drafted by the Toronto Blue Jays in the 12th round of the 2013 MLB Amateur Draft.  He hasn’t made many Jays’ top prospect lists in recent years and struggled early in his pro career.


In 2015, things started to come together for him.  In 55 innings at low-A Lansing, Mayza showed off his swing and miss stuff with a 10.02 K/9 that put him between Toronto’s two highest regarded pitching prospects, Sean Reid-Foley (12.79 K/9) and Connor Greene (8.69 K/9).  Last year, he earned a promotion to high-A Dunedin and used his strikeout ability (9.62 K/9) to put up a 1.66 ERA (6th best in the Florida State League among pitchers with 40+ IP) and 2.31 FIP (4th best).  A short promotion to Double-A New Hampshire didn’t go as well, walks being a particular issue.


Nevertheless, Mayza’s performances over the last couple of seasons have helped establish him as someone from the Jays’ secondary group of prospects who could end up in the big leagues.  The one thing driving this potential is his fastball.  Jays fans have begun to notice that his fastball sits at 95mph and tops out at 98mph.   A Mets fan watching a Dunedin Blue Jays vs. St.Lucie Mets game last April even felt his fastball was impressive enough to tweet about.  We also have some corroboration from Pitchf/x data captured during the 2016 Arizona Fall League.


Which brings me to the focus of this article: How special is a lefty reliever who can sit at 95mph?


The documentary Fastball sheds some light on this.  One particularly relevant part of the film examined the difference between a 92 and 100mph fastball.  In a nutshell, the human brain can process and react to a 92mph fastball but can’t really do the same with a 100mph fastball.  It’s actually pretty cool that the limit to our ability to throw a ball 60 feet 6 inches is roughly in balance with our capability to process and react to a ball thrown 60 feet 6 inches away.  A faster fastball is also trickier to hit because it doesn’t get pulled down by gravity as much as a slower one.  Batters are used to getting 90mph-ish fastballs, so that vertical difference messes with their swing.  While a 95mph fastball won’t be as difficult to hit as a 100mph fastball, it should be much trickier to hit than the low-90s fastballs most hitters will see.


Let’s start with some big picture data.  From 2014 to 2016, 276 LHPs came on in relief and earned at least one out.  Only 12 of these had an average fastball velocity of 95mph or more.



Five of these lefty fireballers are currently good MLB relievers, another five are prospects who have only had a taste of the big leagues, one is a good starter and only one is no longer part of an MLB organization.  So, for now, we can say that 1) 95mph+ lefty relievers are rare and 2) over the last three seasons, half of them were regular pitchers in the major leagues.


Now, let’s dig a little deeper.  We’d like to see if there’s a noticeable difference in quality between lefty relievers with different fastball velocities.  So, let’s group these pitchers according to fastball velocity and calculate the simple averages of some key pitching stats for each group.  While we’ve focused on 95mph+ fastballs, the top group will include all those with fastballs that averaged 94-97mph.  The main reason for doing this is the small sample size of hard-throwing pitchers.  Note that this group leaves out Aroldis Chapman‘s 100mph fastball.  He is an obvious outlier and I’d rather answer this question without his help.


One important choice needs to be made, which is the minimum innings a pitcher needs to have pitched over the last three seasons to be included in our calculations.  If the minimum is too low, we’d be including pitchers whose stats don’t really reflect their quality.  If the minimum is too high, we’ll just be focusing on the pitchers good enough to stick in the majors.  A minimum of 10 IP seems like a good balance.


Finally, there are many statistics that we can focus on.  Ultimately, every at-bat amounts to one of four things: a strikeout, a walk, a home run or a ball in play.  As such, it makes sense to use a statistic that measures each of those outcomes:  strikeout rate (K%, percentage of batters the pitcher strikes out), walk rate (BB%, percentage of batters the pitcher walks), home runs allowed per nine innings pitched (HR/9) and batting average for balls in play (BABIP).  Additionally, I’ll examine three statistics that capture a pitcher’s overall quality:  fielding independent pitching (FIP, which tries to isolate a pitcher’s performance), earned run average (ERA, which is simply the number of earned runs allowed per nine innings) and weighted on-base average (wOBA, which estimates the overall offensive production a pitcher allows).



In general, a 94-97mph fastball is a very useful thing.  While there is usually a steady improvement in performance as fastball velocity increases, there is often a more pronounced change from the group sitting 92-94mph and the group sitting 94-97mph.  A 94-97mph fastball takes nearly a full run off of one’s FIP, at least a third of a run off of one’s ERA and at least thirty points off of one’s wOBA against.  Interestingly, it seems that most of the improvement comes from a stronger ability to strike out batters and avoid giving up home runs.  On average, the fireballers in our sample don’t have particularly better BB% or BABIP.


This all seems logical.  A 94-97mph fastball is harder to keep track of and make good (or any) contact with, limiting home runs allowed and increasing strikeouts.  Walks, on the other hand, are likely more correlated with command than power.  Moreover, a ball put in play is generally considered a lottery ticket.  Pitchers don’t seem to have much control over where one goes.  I can even believe that a ball put in play off of a 94-97mph fastball is moving faster, increasing the likelihood that it turns into a hit.  Nevertheless, a high speed fastball coming from a lefty reliever does seem to be an effective weapon.


Now, let’s examine this data in a slightly different way.  Averages can be useful, but it might be even more useful to know how many pitchers in each group meet the MLB standard.  After all, we are interested in getting an idea of how likely it is that Tim Mayza’s 95mph fastball will eventually put him in the Blue Jays bullpen.  I used the average performance of all MLB relievers in the 2016 season as an estimate of the “MLB standard” and calculated the percentage of pitchers in each group who met that standard during their time in the majors.



The usefulness of a 94-97mph fastball seems to jump out even more now.  Pitchers with a 94-97mph fastball were significantly more likely to meet the MLB reliever average for  K%, HR/9, FIP and wOBA.   They were slightly more likely to do so for ERA.  80% of fireballers met the MLB average in these statistics.  They were most likely to have a sub-MLB average walk rate, doing much better than pitchers with mid-level fastballs (88-94mph) and slightly better than the low-power/high-command pitchers with fastballs sitting at 83-88mph.  Once again, BABIP was not correlated to fastball speed.  And, in case anyone was curious, Chapman met the MLB average in all categories except for BB% (11%) and BABIP (.298).


All of this makes a lot of sense.  The documentary Fastball looked at 92 and 100mph fastballs and found that the former are relatively hittable, while the latter are relatively unhittable.  So, we would expect pitchers with fastballs in the 94-97mph to be quasi-unhittable.  As for Tim Mayza, there’s still a lot of work to be done before he is an above-average major league reliever.  Like most young power pitchers, the biggest question mark is his command.  At the same time, he’s already throwing what would be one of the fastest pitches in the majors and has a power slider that could be a dangerous secondary pitch.  I look forward to watching him try to put it all together.




*Featured Image Credit: C Stem- JFtC







Jeff Quattrociocchi

I'm an economics professor in the GTA whose lifelong love for the Jays was reignited by that magical August of 2015 and the amazing moments since.