We are deep into prospect ranking season, and one thing it does every year is thrust me into the middle of the minutia. Last week that got me ranting a bit on Twitter about Matt Vierling and the gap between public prospect rankings and Phillies fan perception. One of the big sticking points is that he hit .248/.331/.359 in AAA sandwiched around being outstanding in AA and great, but in a bit of an unsustainable way in the majors. This downturn in AAA is a giant red flag for me, not because it is a knock against Matt Vierling, but because it is setting off alarm bells in pattern recognition.
Earlier in 2021, after Jean Segura was injured another prospect had an unsustainably good time in the majors and then just cratered in AAA, and that was Nick Maton. For those than don’t remember, Maton hit .256/.323/.385 in the majors and .199/.332/.345 in AAA. Maton wasn’t the only other one either, Rafael Marchan looked competent in the majors, but hit .203/.283/.232 in AAA. The only other prospect to see a serious run in the majors, but not see a real change in AAA was Mickey Moniak. Now Moniak has historically been coached with his family, so there may be a reason he could be an outlier (this is true on the flip side for lack of improvement).
Prospects struggling in the high minors isn’t by itself a red flag, especially when they are not elite prospects, but what was a red flag is when they all showed the exact same characteristics in AAA. All stats from Fangraphs.
| Nick Maton | Matt Vierling | Rafael Marchan | ||||||
| Year-Level | GB Rate | Oppo rate | Year-Level | GB Rate | Oppo rate | Year-Level | GB Rate | Oppo rate |
| 2017-SS | 34.6% | 30.5% | 2018-SS | 35.4% | 25.0% | 2018-SS | 42.9% | 38.0% |
| 2018-A | 33.8% | 26.0% | 2018-A | 40.0% | 33.3% | 2019-A | 43.1% | 35.9% |
| 2019-A+ | 34.4% | 27.9% | 2019-A+ | 35.1% | 33.5% | 2019-A+ | 43.5% | 39.4% |
| 2019-AA | 25.0% | 14.3% | 2021-AA | 39.7% | 29.6% | 2021-AAA | 48.9% | 42.4% |
| 2021-MLB | 32.9% | 25.0% | 2021-AAA | 50.3% | 38.0% | 2021-MLB | 40.5% | 16.7% |
| 2021-AAA | 45.8% | 31.3% | 2021-MLB | 53.8% | 32.7% | |||
*Marchan’s 9 PAs in MLB in 2020 and 5 PAs in AA in 2021 removed due to sample size
What we see here is a mostly established pattern of output then punctuated by a strong spike of ground balls and opposite field contact. These two things jump out in that they are low-impact contact. There is a lot of things said about launch angle over the years, and it is certainly a stat that is misused and had led to some bad swings being created, but it is irrefutable that ground ball contact leads to less impact because it rarely becomes extra bases and is converted to an out at a high rate. As for opposite field contact, players generally get to more hard hits to their pull side, and so opposite field contact is not bad (and may be a consequence of the ground ball contact), but it can be less impactful for a player without plus or better strength.
I am not a hitting coach or instructor so I am not going to break down swing changes, but we can start to try and isolate the cause of this change. The first place would be the AAA staff in general. We actually have a very small sample size of batters in AAA that both got a large sample size of at bats and were not veterans. Those we do have are Darick Hall and Dalton Guthrie. Hall’s ground ball rate went from 41.6% in 2019 to 42.4% in 2021, and Guthrie posted a 49.2% and 49.0% rate at AA and AAA. In Cornelius Randolph, who we know underwent a swing change in the offseason, a decrease in ground balls, which would correspond with his efforts to tap into more power.
If it wasn’t AAA coaches, was it a minor league org philosophy. Realizing that we are talking about an organization partnered with Driveline and run by the Director of Hitting for Driveline, Jason Ochart, and that Driveline has been at the forefront of both pushing “modern” hitting techniques and being critiqued about them, this sort of feels like a fruitless effort. However, let’s take Johan Rojas, the current best hitting prospect in the system and guy who hits it on the ground too much anyway, as our test subject of dev changes. With the Clearwater data we have, I did a crude breakdown of contact types with anything under launch angle of 10 as a ground ball, 10-25 a line drive, 25-50 a flyball, and anything over 50 a popup (no distinction infield or outfield).
| May | June | July | August | Seaon Total | |||||||||||
| In Play Type | % of PA | Avg EV | Avg LA | % of PA | Avg EV | Avg LA | % of PA | Avg EV | Avg LA | % of PA | Avg EV | Avg LA | % of PA | Avg EV | Avg LA |
| FB | 14.59% | 82.0 | 34.3 | 16.72% | 85.2 | 36.9 | 11.62% | 80.3 | 37.4 | 17.72% | 86.6 | 37.0 | 15.20% | 83.7 | 36.2 |
| GB | 67.28% | 84.0 | -21.0 | 63.10% | 89.9 | -9.7 | 40.53% | 84.5 | -19.0 | 53.09% | 87.2 | -15.4 | 58.48% | 86.4 | -16.3 |
| LD | 8.41% | 91.4 | 18.9 | 12.39% | 98.5 | 17.2 | 29.46% | 94.7 | 15.8 | 20.33% | 87.7 | 14.5 | 15.67% | 93.4 | 17.0 |
| PU | 9.72% | 71.0 | 57.6 | 7.79% | 61.7 | 61.2 | 18.39% | 82.1 | 64.0 | 8.86% | 74.9 | 58.0 | 10.65% | 72.9 | 60.4 |
What we see is a strong drop in ground balls, actually counter to what we are seeing elsewhere. However, it fits into our problem because Johan Rojas spent his spring training in major league camp working with the major league hitting coaches. So now we see a prospect actively being untrained from behaviors from their exposure to the major league coaching staff.
We already know that there was contention between multiple different groups within the Phillies when it came to coaching, especially hitting in the system. So we now need to look at the major league coaching staff.
The problem with looking for swing and approach trends in the major leagues is that successful major leaguers aren’t looking for big changes they are looking for tuneups. However, one player does jump out. Before the Phillies acquired J.T. Realmuto he had changed up his hitting profile, hitting less ground balls and hitting more in the air. The consequence was a large power spike. It was something that carried over into his first year with the Phillies. However, in 2020 Realmuto regressed to his previous self, which also happens to be exactly the way the prospects regressed which is a sharp uptick in ground balls, though in this case without the opposite field spike. This naturally of course also gets us to Alec Bohm who spent 2020 and 2021 beating the ball into the ground very hard. Given Bohm’s lack of track record and some changes over the course of the 2019 season, we don’t have a good baseline for what he normally looks like. What we do know is that his ground ball tendencies showed no sign of improvement in the major leagues.
So what happened in 2020? The Phillies hired Joe Dillon to be their hitting coach. Hailed as the protégé to Kevin Long (who is now the Phillies hitting coach), Dillon was well liked and supported by Bryce Harper. We do know that after 2021 the Phillies fired Joe Dillon and the AAA hitting staff was not retained, but Jason Ochart was. I don’t what Dillon was attempting to do and if there was a method to the madness that was lost along the way, but we do know that hitting the ball hard in the air is how you do good things in baseball and the hard part if getting hitters to do that against good pitchers. What we have is 3 prospects who seriously regressed after interacting with him, a top prospect who needed to be “fixed”, and the Phillies best hitting prospect in nearly a decade stuck hitting ground balls at fielders. It is a lot of damage that ironically it will fall to Dillon’s old mentor to fix. The bright side is that these players might not be irrevocably broken and there might be some bounceback potential with new coaching, but we have said that for many years now with many coaches.
Excellent stuff. Shame you don’t write more.
I would very much like to see a similar stat comparison with Makiel Franko —–first came up was a dynamic , clutch hitter [ singehandedly , almost , took 2 of 3 from Yankees in N.Y. ] and then , up here , gradually became completely ineffective . What happened ?