Is Shawn Armstrong actually good?

The Orioles bullpen has been a bit of a hot mess this season. Their 5.95 ERA and -0.2 fWAR are both the worst marks in the American League. Of course, this comes as no real surprise. The team never really replaced pitchers like Zack Britton, Darren O’Day or Brad Brach, three well-established, albeit imperfect, relievers who were dealt at last season’s trade deadline. Instead, the new regime opted for internal candidates and cheap waiver claims to occupy prominent relief roles in year one of a long-term rebuild.

The results have been predictable, and it’s been made more difficult with spotty performances from the likes of Mychal Givens, Richard Bleier and Miguel Castro. But that doesn’t mean it has all been bad. In fact, the O’s may have lucked into finding their most reliable reliever.

On April 28, the O’s plucked right-hander Shawn Armstrong off waivers from the Seattle Mariners. The 28-year-old had struggled in just four innings with the Mariners in 2019, allowing six earned runs across 3.2 innings. But he had impressed in 2018, striking out 15 batters in 14.2 innings while allowing just two runs. That’s the life of a major league reliever. They hop from team to team trying to prove their worth, which Armstrong seems to have done with the Orioles so far.

Armstrong is fifth on the team with 37.1 relief innings pitched, and yet he leads the club with a 0.6 fWAR out of the bullpen. He’s managed a solid 10.85 K/9 rate despite possessing a middling fastball that falls in MLB’s 38th percentile by velocity. He’s making the most of what he’s got, and it has impressed manager Brandon Hyde enough to give him an important role in the Orioles bullpen.

Armstrong has pitched in 12 games since the beginning of July. The Orioles have won eight of those games. In those eight wins, Armstrong has pitched in the seventh inning or later in all of them. Clearly, there is a trust being developed that Hyde does not have with all of his other late-inning arms.

But appealing surface-level numbers do not always indicate future success, especially for a relief pitcher, which is perhaps the most volatile role on a major league roster. In order to figure out whether Armstrong has the goods to stick long term we need to dive a bit deeper.

The first stop is Armstrong’s Baseball Savant page. There we will find that the New Bern, North Carolina, native is an elite pitcher in one of modern baseball’s favorite metrics, spin rate. Armstrong falls into MLB’s 97th percentile in spin rate. Why does this matter? FiveThirtyEight’s Travis Sawchick put it well in his article from October:

The more spin a fastball has, the more it appears to rise and resist gravity, and that creates more swings and misses.

Unlike velocity, which can be trained, a pitcher’s fastball spin ratio is thought to be extremely difficult to alter naturally.

So, there is one point in Armstrong’s column. He has a high spin rate, and likely will continue to have one as long as he stays healthy

That high spin has also helped Armstrong induce generally weak contact. While his 11% barrel rate is near the bottom of the league, his hard hit rate, average exit velocity and expected batting average against are all above average. This has led to a .253 BABIP since joining the O’s.

For many pitchers, a .253 BABIP could be a warning sign that they have been a bit lucky and are due for a downturn in performance. But Armstrong has made a habit of putting up numbers like this. His career BABIP is just a touch higher at .262. Once again, this is likely the result of weak contact caused by a high spin rate, plus his high fly ball rate (46.8%).

How often all of these fly balls he allows have turned into home runs may be the area of Armstrong’s game that has seen the most improvement since making his move to the O’s. His 9.1% home run per fly ball rate is markedly better than the 14.3% he posted with the Mariners and a slight decrease from his 11.1% career rate.

You get the idea. Armstrong is pitching better than he ever has before in his major league career over such a long stretch of time. However, none of his numbers are especially eye-popping. They are simply solid, above-average stats for a major league reliever. So, what’s the catch?

Well, Armstrong has still only thrown 98 total innings and faced 423 total batters as a big leaguer. That’s not a massive sample size, so we don’t exactly know if what we are currently seeing is a mirage or the real deal. On top of that, he is already in his age-28 season. It’s atypical to see a pitcher get better as he gets to this point in his career but rather hold steady for a bit before experiencing a drop.

So, is Shawn Armstrong actually good? Right now, yeah it is fair to say that he is a pretty good relief pitcher. Most, if not all, of his numbers suggest as much. He won’t be mistaken for one of the game’s elite bullpen arms, like Josh Hader or Kirby Yates, but he would probably make any relief corps in the league just a touch better at this moment. That’s not nothing.

How sustainable is his current level of performance? It’s tough to say. The former Indians draft pick is just approaching the point in his big league career where we can start to draw conclusions about his ability, and there aren’t too many aspects of his performance that indicate he is wildly outplaying his numbers on paper. So, there is no reason to believe that he can’t be a 4.00-ERA, slightly above-average type of arm going forward with the chance to be a bit better than that from time to time.

Armstrong is the exact type of pitcher that the Orioles are likely to covet over the next 2-3 years as they continue rebuilding their organization. He is affordable, under team control for years to come and has one outstanding attribute (in this case, high spin rate) that the Orioles can attempt to accentuate. Let’s hope that others can replicate his success over extended periods of time.