Platoons this year have been a hot topic amongst the Phillies fanbase. There are a lot of people that follow the team that have a distaste for them. We’ve seen Rob Thomson utilizing them for much of the season at second base and in left field with a smattering of center field switcheroos to sprinkle in. As the season has gone on, those platoons have gotten more pronounced, no matter the acquisition of Harrison Bader to seemingly lock down the center field job. Even with that trade, Thomson has continued to make sure that right handed hitters are facing left handed pitching and vice versa. Ask the players what they would rather do and almost universally, they’d like answer that regular playing time would lead to better on field results, but it’s been shown that the players are already succeeding in the roles Thomson has been putting them in.
Even then, it might be time to talk about possibly expanding those platoons to include right field.
Earlier this season, we saw that Nick Castellanos was benched for one game when his response to being pulled from the game prior in favor of a defensive replacement was one that Thomson deemed “inappropriate.” Not playing is something that Castellanos does not look at favorably as shown by his stated desire to play every day last year and this year. It’s an admirable trait for a player to have and strive for. It’s not that playing Castellanos in every game is actively hurting the team. He’s one of the few players the team employs that has power from the right handed side…even if his slugging percentage has dropped the past three years and is in serious danger of dropping below .400 if his current slide continues. This is cherry picking stats at its finest, but since June 24, Castellanos has hit .205/.236(!)/.358.* We can say with relative honesty that he’s been pretty bad lately, but has not hurt the team that much in the process. They’re still winning.
*All stats through Tuesday’s game
Yet with the playoffs looming, the team should be considering all their options. One of those options should be platooning Castellanos against right handed pitching and rolling with a different outfield alignment in the hopes of not only boosting the sagging offense the outfield provides as a whole, but also to improve the defense to help the strength of the team: its pitching staff. Rolling with Castellanos in right field on a nightly basis means that they are putting the worst defensive player in the game on field each night willingly. It’s fine to do so if there is offensive production coming from that spot, but as we see, that’s not been happening. It could be merely an extended slump since that is something that we have come to live with from Castellanos, but there are other things to take into consideration here. Let’s explore what that might look like.
In theory, if the team were to platoon in several positions, there might need to be a current platoon that needs to cease for the moment. There simply wouldn’t be the manpower to have more than three platoons at a time. If we chose to use Bader every day in center field, living with whatever he can do against right and left handed pitching in order to keep his glove on the field, and keep Alec Bohm at third regularly, this is what the lineups might look like against right handed and left handed pitching:
Positionvs. RHPvs. LHPCRealmutoRealmuto1BHarperHarper2BStottSosa3BBohmBohmSSTurnerTurnerLFMarshWilsonCFBaderBaderRFKeplerCastellanosDHSchwarberSchwarber
It’s been opinionated that leaving Castellanos on the bench would be putting the team’s best defensive alignment on the field. The question becomes: does that really matter when it comes to this particular pitching staff? As a team, their pitching staff gets outs via the flyball at the fourth lowest rate in the game, using the other two ways of getting batted ball outs much more extensively.
Groundball rateMLB rankFlyball rateMLB rankLine drive rateMLB rank43.2%7th36.4%26th20.3%t-7th
Focus in on who it would be affecting the most, the starting pitching, we can look at the top four starters that would theoretically be the quartet that starts playoff games. Those top four starters – Wheeler, Sanchez, Suarez, Nola – all rely greatly on the groundball to get outs, so again, improving the outfield defense wouldn’t be as much of an issue. Much as we want to think that taking Castellanos out of right field right now would be a huge upgrade, I’d argue that over the course of a few weeks (or even the postseason), the expected improvement would negligible. Would the defense be bad in the outfield on the days when they are facing a left handed pitcher using the above lineup? Unequivocally yes, but we’re talking about maybe a play here, a play there.
During the regular season, this – the outfield defense – wouldn’t have much of an effect, the sheer amount of games and correctly played baseballs outweighing the occasional misstep. But in the playoffs, a misplay can represent a huge swing of things, either in the win probability column or in the vaunted “momentum” column. The team is probably going to live and die in the playoffs by their pitching staff, so the idea of giving it all the defensive support it can get has merit. It would (and should) be worth considering.
But defense is not the only thing to take into consideration.
Instead, let’s think about the offense. Sitting down Castellanos from being an everyday player would also mean taking his bat out of the lineup. If we’re talking his since-6/24 bat, then don’t let the door hit you on the way out. Yet this kind of a slump seems to be a regular occurrence: Castellanos gets into a horrendous stretch and struggles to get his way out of it. As has been said before, you take the good with the bad when it comes to Castellanos and right now, we’re taking the bad. He has shown the ability to get out of it, so perhaps that is what the team is currently waiting for.
Leaning into the platoon a little bit might help mitigate some of that bad by putting him (and others) in better positions to succeed. We have evidence that platooning has helped some of the players play better when put against pitchers that they should be having success against.
PlayerPA vs. LHPslash vs. LHPPA vs. RHPslash vs. RHPB. Marsh59.216/.293/.294237.286/.346/.452H. Bader104.213/.288/.394230.269/.352/.448N. Castellanos145.261/.310/.418330.257/.291/.415M. Kepler58.208/.259/.321314.206/.304/.375W. Wilson49.214/.327/.26211.400/.455/1.000O. Kemp50.250/.340/.432106.227/.283/.340J. Rojas75.224/.288/.31397.224/.274/.271
One thing that jumps out is that Harrison Bader is actually hitting better this year against right handed pitching, so it probably makes the most sense for him to be seeing regular at bats out of everyone in the outfield rotation. However, as you can see, there are clear platoon advantages to take advantage of….except for right field. Castellanos is showing no real huge splits while Kepler, the one who should be taking advantage of right handed pitching, has not shown a clear aptitude for doing so in 2025.
So why would they take Castellanos out of the lineup then?
We don’t really need to talk about the left field platoon. Whatever the team is doing seems to be working. No, the focus would remain in right field. The biggest thing to see is the difference in defensive value between Castellanos and Kepler. No matter what metric you so desire to look at, Castellanos is at or near the bottom. Based on OAA (outs above average), he is the worst outfielder by quite a ways. Kepler, in left field for all but a few innings, has been average by OAA, but in his past few seasons in Minnesota, he was rated rather favorably, especially when compared to Castellanos. Were they to give more credence to getting a better glove in right field at the expense of whatever offense Castellanos could provide when right, it’s not really much of a decision.
In short, there isn’t a clear cut choice here. While sitting Castellanos down full time is probably never going to happen, there is some evidence that perhaps a platoon is in order. One would have to assume that Kepler will at some point start hitting right handed pitching due to some numbers from his past, but we’re also into August and he’s not hitting no matter who is on the mound. The only assumption to make about Kepler is that he probably won’t do anything anyway. The defensive upgrade benching Castellanos would theoretically give would probably be mitigated by putting an inferior bat in his stead. Even the possible platoon that could be employed doesn’t show too many signs of actually working outside of Kepler catching a few more balls that Castellanos might not get to.
We also have to factor in the human element into whatever decision making Thomson would be going through. Castellanos did not respond favorably when removed for a simple defensive replacement in a game in June. How would he react to being demoted in favor of a platoon in the heat of a pennant race? While the first, gut reaction to that question might be “who cares?”, there is something to keeping a happy, content clubhouse in the thick of a pennant chase, something that Thomson might value.
With this little bit of a lead the Phillies currently have, it might be a chance for them to at least try and see if a platoon in right field would work. Even if there are things that we would like him to change with regards to his on field decision making, one thing Thomson has excelled at is handling the players and the clubhouse. A conversation with Castellanos might be something he wants to have to show the data, outside of whatever we have publicly available, to show why a platoon could work. If it doesn’t, they’re right back where they are now.