(When) Will Albert Pujols Reach 700 Home Runs?

I’ve been having fun producing estimates of when Aaron Judge might hit his 60th, 61st, and 62nd home runs this season. It’s cool for multiple reasons: I love home run chases, like most baseball fans, and I also like coming up with ways to answer seemingly difficult questions via simulation. It’s one of the same reasons I like writing about baseball in the first place: I think it’s very neat that I can think about baseball both very tangibly (Randy Arozarena’s baserunning) and abstractly.

Since I have the technology, I’ve gotten a fairly obvious request a few times in the past week: do it for Pujols. His improbable quest for 700 homers has turned into an unlikely quest, and now a “wait could he?” quest. At 697 dingers, he’s within hailing distance of a momentous number to retire on. I’m going to use the same tools that helped me model when Judge might hit some big homers to do the same for Pujols.

The bare bones of this system will be the same. I started with the Cardinals’ remaining schedule and the park factors for right-handed hitters in those stadiums. Almost immediately, though, I took a detour, because the Cardinals don’t use Pujols like the Yankees use Judge. At this stage in his career, Pujols is at his best against left-handed pitching. He also needs more off days than Judge, eminently reasonable given his age. That creates a playing time puzzle, so to figure out which games Pujols will play in, I used Roster Resource to work out which days I expect opposing teams to start lefty pitchers. On those days, I project Pujols to start and get three plate appearances (against lefties) 30% of the time, four (three against lefties) 55% of the time, and five (three against lefties) 15% of the time. This is definitely not perfect, but as a rough approximation, it’ll do.

On days where the Cardinals face righty starters, I got creative. If Pujols didn’t play the previous day, I assumed manager Oliver Marmol would always play him. That’s pretty close to how he’s been used this September; out of five days where Pujols sat out or pinch-hit the previous day and the Cardinals faced a right-handed pitcher, he has started four of them. If he did play the previous day, I gave him a one-in-five chance of playing against a righty (again mimicking reality). In those games, I gave him three plate appearances against a righty and one against a lefty. Otherwise, I projected him for one pinch-hit plate appearance against a lefty.

I made one other executive decision: the Cardinals have a doubleheader on September 17, and the Reds will very likely start a lefty in one of the two games. I assumed Pujols would sit the other game entirely to stay fresh. Aside from that, the remaining Cardinals schedule should provide him as much rest as he’s enjoyed over the last month of regular playing time.

There’s one last complication: the Cardinals play the last six games of the year against the Pirates, first three in St. Louis and then three in Pittsburgh. I think Marmol will prioritize Pujols hitting his 700th homer in front of a home crowd, and the division race is likely to be settled by then, so I simulated full games for the first three, with two of the games in Pittsburgh also being full games. I expect that if Pujols is one homer short in the last series of the season, the team will do everything it can to get him over the line.

Next, I worked out expected home run rates against lefty and righty starters. We’re into the realm of guesswork here, but I simply used his home run rate against the appropriate type of pitcher over the past two years. Is that flattering to Pujols, who probably isn’t a true-talent 140 wRC+ hitter (his line this year) given that he put up an aggregate 84 wRC+ over the previous five years in seven times the sample size? Oh yeah, most definitely. But I can believe that he’s seeing the finish line now and emptying the tank completely, which probably counts for something, and anyway, it’s my simulation so I get to do what I want. The results of that look like so:

There’s a lot of guesswork involved in this, but that comes out to an 80% chance that Pujols will hit his 700th, with a three-game set against the Dodgers and their predominantly lefty rotation the series where it’s most likely. Unfortunately for Cardinals fans based in St. Louis, the previous series against the Padres has the second-best chance; San Diego is lining up to throw two lefties in the three games, which certainly helps.

That 80% figure sounds high to me, so I ran another version with different home run rates, halfway between what we’ve observed over the last two years and what he’s projected for the balance of the season. That required a bit of platoon-rate finesse, so there’s some guesswork to this, but hey: this whole article is about guesswork. If these rates are closer to the truth, Pujols has a two-in-three chance of reaching 700:

The Dodgers series still looks like the best chance at history. The last home series of the season, against the Pirates, looks pretty good too, and you can almost guarantee that he’ll play in all three of those games for a grand sendoff, so even if you don’t get to see a milestone homer, you’ll get to see plenty of Pujols plate appearances.

If this feels like a too-cold distillation of a legend’s last ride into a few tables of numbers, I sympathize. If you’d prefer to live in suspense, I don’t blame you. But I think it’s fun to parse numbers like this, and Pujols’ chase for 700 is a great excuse to break them out. If you’re in Los Angeles next week and want to see history, you’ve got a decent shot.