Reliever David McKay packs a killer curveball

After a busy couple of weeks around the league with players being released and rosters reset for the stretch drive, the Tigers finally put their waiver priority to work for them last Tuesday. They claimed right-handed reliever David McKay from the Seattle Mariners. In the pantheon of front office moves, this doesn’t figure to be terribly impactful, but the 24-year-old has potential and should make for an interesting project for Toledo Mud Hens’ pitching coach Juan Nieves.

That potential was very much on display in McKay’s first outing for the Triple-A Toledo Mud Hens on August 10th. The young right-hander took over from Kyle Funkhouser in the sixth inning with a man on second and no outs. McKay proceeded to punch out the next three hitters to escape the jam. He struck out three hitters in the seventh as well. One of them did reach first after swinging at a wild pitch that got away from catcher Kade Scivicque, and so McKay also recorded a pop out in the seventh. Technically he recorded seven outs in two innings of work.

McKay was initially drafted by the Kansas City Royals back in 2016. He worked as a starter, but was plagued by a mediocre fastball. The Mariners traded for McKay and converted him to a reliever in 2018. The hope was that he’d see a velocity bump and become a viable late innings option.

McKay debuted in the major leagues for the Mariners back in May for a brief but reasonably successful stretch of games before returning to Triple-A Tacoma. However, the control issues plagued him throughout most of his season at Tacoma as well. The Mariners called him back up in July briefly and things didn’t go so well. He posted four rough outings in a row from late July to early August and the Mariners decided to move on.

McKay really spins his curve

McKay’s calling card is a nasty curveball with some tilt and an elite spin rate. The curveball boasts an average of 3016 rpms, which is sixth best in the major leagues among pitchers with 50 or more curveballs registered in Statcast this season. Thrown at 78 mph on average, the pitch has excellent bite and McKay can bend it laterally away from right-handed hitters when he wants to. It’s a pretty dominant curveball when he’s in command of it. The problem, of course, is that he sometimes isn’t in command of it.

Let’s take a look at a couple of samples from his major league tour with the Mariners early this season.

The first clip is a first pitch curveball on the outer edge to Angels outfielder Kole Calhoun. Because McKay doesn’t throw a changeup, the curveball functions as both a swing and miss offering, and also as his offspeed pitch to lefties. He steals strike one here on a pitch that Calhoun probably couldn’t do much with even if he’d tried to take it the opposite way.

The second clip shows McKay using the curveball more like a slider. It starts on the outer edge, breaking hard off the plate and down. The horizontal break is a little more evident to his glove side.

That pitch is the reason the Tigers picked him up. Of course, everyone knows an elite spin rate curveball is a good thing in a general sense. Yet the Mariners released him anyway. McKay has to be able to spot and shape it, because he doesn’t necessarily have other strong weapons. He doesn’t have premium velocity or movement, and he’s never been been much of a surgeon in terms of fastball command. But there might be a couple of things the Tigers can do to help him improve.

The fastball may be a candidate for change

McKay complements his curveball with a fastball sitting 93-94 mph. The heater gets labeled a sinker at both Statcast and FanGraphs, but it seems to run more than it sinks. Averaging 2311 rpms, McKay’s fastball actually has a modestly above average spin rate. That’s not usually ideal for getting the ball to sink. And it doesn’t appear to work. McKay gets more flyballs than grounders, and his “sinker” doesn’t really sink. A consistent flyball profile on batted balls throughout his minor league career speaks to the possibility that he should stop fighting it, and try to become more of a high fastball-curveball pitcher.

Typically, we think of pitchers as being built from their fastball up. However, in a case like McKay’s, where his curveball is quite obviously his standout offering, perhaps a bit of reverse engineering is required.

Tightening the tunnels

Pitch tunneling is rapidly becoming much better understood and described, but the concept has always existed under a variety of names. Essentially, the idea is to match paths on release to make all pitch types look the same out of the pitcher’s hand for as long as possible. The longer it takes hitters to recognize the pitch, the less time they have to adjust and make contact.

The Astros have rapidly become the poster child for organizational success in this area, among numerous others, as they’ve taken numerous pitchers with high spin rate breaking balls, and converted them to pairing the breaking stuff with riding fourseam fastballs instead of twoseamers and sinkers. Gerrit Cole is the standout example as his career has taken off into the stratosphere since ditching the twoseam paradigm for his fourseamer, but they’re already at work doing the same thing with former Toronto Blue Jays’ starter Aaron Sanchez, who Astros GM Jeff Luhnow acquired on the cheap at the July 31st trade deadline.

Take a look at McKay’s second strikeout in his Mud Hens’ debut. Not only is this a heck of nasty curveball, but note how it seemingly pops out of his hand on almost an upward trajectory. The initial trajectory looks like it should carry the pitch head high past the batter before gravity and the extreme topspin take over. That’s a curveball that generally “tunnels” best with a riding fourseam fastball.

Now, let’s take a look at a 96 mph fastball from the same outing. McKay showed good velocity, touching 97 mph in the sixth inning, though in his second inning of work he was back down to consistently throwing 93-95 mph.

There are a couple of takeaways here which will bear watching.

First, the fastball looks like it could play up in the zone. Obviously Scivicque wanted it down, but it seems to have some life up there. Where he ended up locating it may actually be a better usage of his fastball-curveball combination. In general, McKay tends to miss up with his fastball. Whatever grip he’s using, McKay and his catchers could certainly try throwing at the top of the strike zone more often. If he’s effective there, it would only enhance his ability to strike hitters out with the curveball. McKay’s curve has enough break to start at a hitter’s eyeline and still drop completely off the table. Pair the two and they should complement each other well.

Based on viewings of his time in Seattle, McKay pitched exclusively out of the stretch and looked like a bit of a short strider. He didn’t get a lot of drive toward the plate and his arm action was pretty stiff, featuring a prominent “inverted W” position. That lack of momentum may impact his ability to be balanced and consistent. Instead, sometimes he over-rotates and flies open toward first, while on other viewings he blocks himself with his step and winds up throwing crossfire a little bit.

However, in his one outing with the Hens, he looked like he was standing upright a little more and trying to maintain that spine angle throughout his delivery. His whole motion looks a little more synchronized and relaxed than many examples from earlier in the season. His extension toward the plate looks a little better as well, and he appeared to be throwing more fourseamers than sinkers. It’s subtle, and I wouldn’t bank on anything just yet, but it’ll be worth watching to see if the Tigers really have him making notable adjustments to his delivery.

He also appeared to be throwing fairly hard and touched 97 mph according to the broadcast. McKay has seen his velocity tick up since his conversion to relief back in 2018, but most scouting reports still had him as a low 90’s guy prior to this season. For a guy who averaged 92.8 mph in the majors to sit roughly 95-97 mph for one inning is a positive sign.

Here’s look from behind home plate from our friends at the Tigers Minor League Report.

Changing the way he uses his fastball to help it pair better with the curve is relatively straightforward. The high fastball-curveball pairing can be tried and discarded if it just doesn’t work for McKay. But McKay’s real issue this season has been the walks allowed, and the underlying inconsistent control. Fixing those control problems is tougher.

The fact that McKay’s heater is fairly average in terms of velocity and spin rate means that he’s not going to have a lot of margin for error with it in the majors if he can’t spot it around the edges. Finding a bit more velocity and changing how he uses it with an eye to his spin profile would help. Certainly he can use a heavy percentage of curveballs, and he probably should. But without good location the fastball is going to get hit in the majors.

Obviously, young relievers with control issues are a dime a dozen, but most lack the potential dominant pitch McKay packs in his curveball. This was a quality pickup by the Tigers’ front office. While it may not work out, they’ve added another young pitcher with talent to the farm system at no cost. If they can help him fine tune his delivery and refine his pitch mix, the Tigers could have a solid young reliever.