Marcus Stroman, a tale of two pitchers

Marcus Stroman, the Toronto Blue Jays' proclaimed ace, had another rough outing at home Saturday afternoon against the Boston Red Sox. His afternoon ended after just five and two third innings pitched, allowing seven runs on 11 hits, two of which were home runs. The poor outing raised his ERA on the season to a miserable 4.46 which doesn't accurately describe the pitcher he's been this season.

That is, depending on where he takes the hill, he can go from being the ace he portrays himself to be or just another guy that takes the ball every five days. More specifically, when Stroman takes the hill at his home Rogers Centre he struggles more than anywhere else but when pitching on the road, he takes on the appearance of a man trying to do his best Clayton Kershaw impersonation. Looking at just his ERA as a metric to support this theory, Stroman owns a despicable 6.39 ERA at home, but a lethal 2.45 ERA on the road.

The question that keeps you up at night, why?

One theory that Blue Jays commentators Buck Martinez and Pat Tabler posited Saturday was that Stroman had faced stronger teams therefore offences when pitching at the Rogers Centre. To some degree, that theory does carry some weight. At the Rogers Centre, Stroman has pitched six games facing the Red Sox twice, along with the New York Yankees, Chicago White Sox, Los Angeles Dodgers and Tampa Bay Rays. On the road, he's faced the Rays twice, the Baltimore Orioles, San Francisco Giants and Minnesota Twins. Conceivably, you could make the argument that the stronger competition for Stroman has been at home. Using wRC+ as a metric that is all encompassing offensively, the teams who have faced Stroman at the Rogers Centre have averaged a wRC+ of 104.67 whereas those on the road averaged 100.6. You can see that there is a bit of a disparity between the opposing competition levels of course, but is it enough to account for nearly tripling his earned run average? I'm not sure about that.

When you look closely at Stroman, beyond the high socks and charisma of a 5'9" warrior at the Rogers Centre, you truly can see the tale of two pitchers. Once he steps off that plane and onto an American soiled mound, Stroman reduces his walks and induces more weak contact. The odd thing is that he's putting the ball on the ground at nearly the exact same rate at home as he does on the road. Anyone who knows Stroman knows that that is a key to Stroman's success as he sits second in the entire Major Leagues with a 59.9 per cent groundball rate. Of course, the pitch that's most responsible for this is his bread-and-butter pitch, the sinker.

Now, a little caveat to the following analysis. I pulled all my pitch f/x data from Brooks Baseball regarding Stroman's pitch data. While it's typically reliable, there have been instances where they, like everyone, have struggled to determine what exact pitch Stroman is throwing because of his the amount of movement he's able to put on the ball.

That said, the data on his sinker is pretty convincing. When you compare the batting average against his sinker at home against the batting average against it on the road, you come to a disconcerting and extremely confusing conclusion. At home, batters own a .370 batting average against the sinker but on the road it falls off a cliff to just .188. What gives?

When you look at all the variables that go into the pitch, it becomes even further hard to understand.

Looking at each measure, there isn't much variation. Sure there is certainly a difference in movement home and away that is noticeable but by astronomical measures. The largest disparity is spin rate and typically a higher spin rate on a pitch would increase the amount of swing and misses on the particular offering. A potential explanation for this disparity between home and away is that hitters are hitting line drives almost twice as often at home as they do on the road. Again though,  you're still left wondering why that is.

In this, there's not a lot to make sense of. He appears to be getting just as much velocity and movement on the pitch but is getting completely different results.

How to fix the situation?

One change Stroman could explore in the future would be to change up his pitch location.

Brooks Baseball

As you can see, Stroman is pitching down in the strike zone an awful lot on the season. A professional approach to facing Stroman would simply be, if you see a ball up, let it go because he's more than likely going to come down and give you a pitch on the bottom of the strike-zone that you can handle.

Now, that's not to say that throwing down is inherently ineffective for Stroman. When you throw with as much movement as Stroman does, it can be an extremely effective game plan. However, if a hitter knows that's the only location you're going to attack, you forfeit the element of unpredictability. Consequently, the movement on your pitches becomes less of a factor. If hitters can zero in on a general area the only other thing they have to do is determine the pitch, which can be extremely hard for us arm-chair baseball players, even in a video game, but can seem remarkably easy for major league baseball players.

Another approach Stroman could incorporate into his repertoire would be the theory of effective velocity. Essentially the idea of effective velocity is throwing the ball in different locations that force a hitter to react quicker to the pitch, effectively giving off the perception that the ball is travelling faster than the radar gun says it is. (I've included images to demonstrate how he's currently pitching). The black line in each picture is the effective velocity line. Any pitch along this imaginary line has the same perceived velocity as the radar gun reading. Any pitch closer to the batter forces a hitter to react faster and thus has a higher perceived velocity than it actually is.

Right handed hitters:

Brooks Baseball

Left-handed hitters:

Brooks Baseball

As you can see, facing right-handed hitters, Stroman's hottest area is directly on the effective velocity line--down and away. Rarely does he venture into the area of making it harder on hitters by coming inside. Against left-handed hitters, the story is quite similar. Most notably, he throws a fair number of pitches away to both-handed hitters which actually reduces the perceived velocity of his pitches and conceivably makes it easier for opponents to generate contact.

Marcus Stroman is an incredibly talented athlete and has overcome adversity I can only read about to try and understand. Yet, he's still fighting. He's still learning the game of baseball, trying to figure out the proper pitch sequences to defeat some of the world's best hitters. After overcoming a torn ACL while proving every doubter wrong about the influence of his height, there's no reason to suggest he couldn't figure this out as well.

It might take a little time and a shift in thinking, but the stuff to become that opening day ace is there. He just has to discover it.