To Swing (Or Not To Swing) At the First Pitch

Sorry for the Shakespearean title; the playoffs make me feel overly dramatic every year. This time, I was inspired by the markedly different approaches of the San Diego Padres and Philadelphia Phillies, who traded blows for five exciting games. The Padres (avatar: Juan Soto) work the count and take walks. The Phillies (avatars: Nick Castellanos and Bryce Harper) sit dead red and swing from the heels. Styles make fights, to borrow a saying from a dying sport, and this one was dramatic.

It got me to wondering: how different were these two approaches, really? It certainly felt like the Padres were watching plenty of hittable first pitches fly by while the Phillies swung at breaking balls in the dirt, but that’s based on my sentiment while watching the game, sentiment that was surely informed by both my pre-existing biases and the broadcasters repeatedly mentioning the disparity throughout the series.

I decided to come up with a test case for aggression to sort things out: swing rate at first-pitch fastballs in the strike zone. Taking raw swing rate is too reductive; pitchers react to opposing tendencies, so a swing-happier team might see more pitches outside the zone, and thus swing less, without changing their approach. Likewise, you could imagine a set of starting pitchers who simply couldn’t locate; even if the Phillies were keyed up to swing at everything, a fastball a foot above the strike zone results in a take every time, what with Javier Báez missing the playoffs and all.

In the regular season, those passive Padres swung at 45% of the first-pitch in-zone fastballs they saw. The free-swinging Phillies swung at 43%. Wait, what? That’s right – for the season as a whole, San Diego actually took the more aggressive approach. If you only look after the trade deadline, when Soto brought his count-working ways out west, they’re tied at 43.7%. Despite their different reputations and key players, the two teams attacked the pivotal first pitch similarly.

In the playoffs, that changed. The Phillies have swung at 53.8% of the first-pitch fastballs they’ve seen in the strike zone through three rounds of playoff action. The Padres swung at just 39.9%. That’s a big gap, one that suggests there’s something to the differing ways the two teams play. It wasn’t just sentiment; the two teams really did behave differently in their series.

To further illuminate this difference, I added a few more categories. Here’s each team’s swing rate divided by location and pitch type:

In plain English, the Phillies were more aggressive almost across the board, but the Padres swung more often when they got early secondary pitches to hit. That’s likely no coincidence; they saw a whopping 92 secondaries in the zone to start at-bats in the playoffs, 23 more than the closest trailer (the Phillies, naturally enough). When pitchers are attacking a team in a predictable way, it’s hardly a surprise that they’d adjust to that somewhat; they swung at just 36.5% in the Soto-era regular season.

This only raised further questions for me. Namely: who was right? By one simplistic measure, it was the Phillies. They’ve seen 388 first pitches, and per Baseball Savant accrued 5.6 runs above average on those pitches. The Padres saw 446 first pitches and stacked up just 2.8 runs of value. Run value considers how much the result of each pitch changes a team’s run expectancy. Taking a ball is good. Taking a strike is bad. Hitting a double is great; hitting a homer is even better. So case closed; be like Philadelphia and go wild.

Only, that’s ignoring a lot of context, and context really matters here. For example, the Phillies have generated 11.3 runs above average in the playoffs as a whole, easily the most in the postseason. The Padres totaled 3.4 runs below average across all postseason at-bats. Teams as a whole have been below average this year; offense has been way down. In fact, by Baseball Savant’s reckoning, the Phillies are the only team to accrue positive runs above average in the postseason, period.

That means that in all counts other than the first pitch of each at-bat, the Padres were much worse than the Phillies. Their approach actually worked for them, relatively speaking. Put another way, the Padres got into 1-0 counts more frequently than the Phillies, and 0-1 counts less frequently. They also put the ball into play more frequently despite swinging less frequently; that’s because fewer of their swings were at bad pitches, naturally enough. In fact, despite their reputation for patience, the Padres had the second-highest rate of fair contact on the first pitch across the entire playoff field.

But wait, because it’s still not over. When the Phillies made contact, they made it count. They hit .400 with an .844 slugging percentage when they put the first pitch into play. The Padres were no slouches there; they only hit .271, but with a .576 slugging percentage, and they did it in volume. For an offense that slugged .366 overall, and .531 on contact, the first pitch was a godsend.

Another wrinkle: the Padres were bound to hit fairly well on first pitches, because those first pitches were often in the strike zone. They saw the second-highest rate of first-pitch strikes, behind only the Braves. Meanwhile, the Phillies have seen a roughly average amount; Padres pitchers, in particular, threw plenty of secondary pitches and avoided the strike zone. Philly swung away and accepted the extra strikes; as we learned above, it still worked for them thanks to their prodigious power on contact.

Was this series a referendum on whether you should come out swinging or wait for your pitch? I’d argue that it was essentially the opposite. The Phillies gripped it and ripped it; they didn’t sit around waiting for the game to come to them. The Padres went full Soto, sitting on particular pitches and locations and accepting strikes if they didn’t get what they wanted, while racking up favorable counts when opposing pitchers missed the zone.

The approaches couldn’t be more different. The results? Well, the Phillies have had the best offensive results on the first pitch this postseason. The Padres? They’re second. There’s more than one way to handle yourself at the plate. The first pitches of this series didn’t determine the outcome; the teams played to a draw there, and the Phillies just plain out-hit the Padres in the end.

You can’t reduce baseball to a single black and white decision. That doesn’t mean it isn’t fun to try. I absolutely love how different each team’s approach to hitting was, and yet how well both worked. For the record, the Padres and Phillies were both middling on the first pitch this year. In the regular season, the Phillies were 1.6 runs below average on first pitches. The Padres were 1.9 runs above average. In the long run, perhaps neither approach is right. This October, they both are.