Comparing the Diamondbacks and Phillies ahead of the Championship Series

Neither team was expected to be taking part in the National League Championship Series, which gets under way at Citizens Bank Park tomorrow evening. Both sides entered the post-season as wild-cards, sweeping their opponents in that series, and then faced the winners of their division in the next round. But the champions proved surprisingly little trouble as well. The D-backs rolled past the Dodgers, who had won 16 more regular season games, without dropping a contest. The Phillies took slightly longer to dispatch the Braves, taking three of four despite finishing 14 games back of them in the NL East. And, so, they now faced off in the Championship Series. How might things go?

Let me be perfectly clear. What will determine the result is how well these teams play in the coming games. Everything else is irrelevant. But we may perhaps get an idea by looking at how the two teams have performed across the various elements which go to make them up.

Position players

At the highest level, these two teams are very evenly matched. By bWAR, in fact, they are exactly even, with both Arizona and Philadelphia having received 20.4 wins from their position pkayers. fWAR gives the Phillies a slight edge, but it’s just 0.7 wins (20.4 to 19.7), so is basically within the margin of error. However, the two teams did not reach that figure in the same way. The Philliea are offensively better, with a wRC+ of 105, compared to the D-backs’ figure of 98. However, Arizona makes up the difference by being superior both in base-running and, in particular, on defense where Philadelphia were close to the worst in the major-leagues this year.

We can perhaps focus things down by looking at the two line-ups used by the sides in the Division Series, which were remarkably consistent. Outside the nine starters, both the Phillies and D-backs saw just three PA each for their bench, and it seems likely the managers will stick to a similar approach for the Championship Series. Here’s what each team will probably be using: for each player, we have given the bWAR, fWAR and averaged the two metrics to get a consensus of their value in 2023.

Obviously, a counting stat like WAR does not take playing time into account. However, for most cases on both teams, these nine players appeared close to every day. On the Phillies, Johan Rojas (and, yes, it’s going to be weird seeing J. Rojas on our opponent!) was the only one to make fewer than 126 appearances. He played in only 59 games, which makes his WAR tally all the more impressive: on a rate basis, he might have challenged Corbin Carroll for Rookie of the Year, if his debut had been Opening Day rather than after the All-Star break. Similarly, on the D-backs, Evan Longoria is the only one with fewer than 111 games. All told, the Phillies nine played 1,221 games, the D-backs nine in 1,190 - almost the same.

On that basis, it appears the D-backs have an edge on the position front, based on the nine players who are likely to get the bulk of the playing time in the series. Though at most positions, there is not a huge difference. There are three spots where it’s greater than one WAR. Favoring the Phillies, Trea Turner is better than Geraldo Perdomo at short, and Rojas is better in center than Alek Thomas. But more than countering both of those combined, is the massive gap (5.7 to 1.3 WAR) by which Corbin Carroll is ahead of Nick Castellanos in right field. Take that out, and the difference swings from 2.4 WAR in favor of Arizona, to a 2.0 WAR edge for the Phillies. Carroll’s performance could be the difference maker.

Pitchers

On first glance, this appears to be where the Phillies have a decisive edge. [Note: here I’m sticking purely to fWAR, because Fangraphs offers an easy way to separate our the rotation and the bullpen. Hey, it’s Sunday morning: sue me!] The Phillies had the best pitching staff in the majors this year, worth 24.4 fWAR. The Diamondbacks... um... did not. They ranked all the way down at 22nd, at only 11.0 fWAR. But that figure is misleading, for it includes the dreck from players who won’t be within a million miles of a Championship Series roster. This year, the Phillies had just three pitchers below replacement level, totaling -0.4 fWAR. But the D-backs had TEN in negative territory, worth -1.8 fWAR, narrowing the gap.

On that basis we should do as with the position players: look at the ones who we will see in this series, based on the Division Series. We’re going to look at four starting pitchers, although neither team has yet said what they’ll do for Game #4. The D-backs’ plan might be Tommy Henry, might be a bullpen game, while the Phillies will likely go either with Cristopher Sanchez or Taijuan Walker. I’m going to leave it blank for Arizona, with a value of zero, and average the numbers for Sanchez and Walker on the Philadelphia side. We’re also going with up to eight relievers for each team. AZ used seven, so again, one is blank, and stats are for starts or relief appearances only.

This does confirm the Phillies’ general pitching edge. Looking at these starting pitcher, Games #1 and #2 should be close, but Philadelphia would appear to have a significant advantage in #3 and #4. But a couple of things are worth taking into account here. Firstly, fWAR is a fielding independent metric, since it’s based on FIP rather than ERA. The D-backs defensive edge would come into play here. narrowing the gap, though that was previously factored into the position player side. It’s also worth pointing out that Brandon Pfaadt, and the D-backs’ bullpen in general, are a lot better now. Including his Division Series start, Pfaadt’s ERA over his last 45.2 innings is 3.74.

Taking all of the above into consideration, and adding the advantage of a ferocious home field, I can see why the Phillies are the favorites. Though I don’t think it’s as one-sided as the near-unanimity of the pundits in favor of Philadelphia would have you believe. The gap in regular season numbers is certainly no greater than that between the D-backs and the Dodgers, and you would not have known that from the eventual result. I think it’ll be a very interesting series: Arizona will relish their role as under-dogs, and I don’t think they’ll be overawed by the occasion. Especially if they can shock Philadelphia early, like they did Los Angeles, then anything could happen. After all:

“Everyone has a plan until they get punched in the mouth.”