Is Bryce Harper in the midst of the greatest offensive season in Citizen’s Bank Park history?

Which Phillies player had the greatest offensive season in Citizen’s Bank Park History? Was it Chase Utley? Ryan Howard? Bobby Abreu? Aaron Altherr? (Okay, I’m mostly kidding about that last one, but Altherr did have a .954 OPS and 143 wRC+ at home in 2017.)

Utley had a .458 wOBA at CBP in 2007. Howard hit 29 home runs at the Bank in 2006. Bobby Abreu had 73 weighted runs created at home in 2004.

This year, Bryce Harper has a 175 wRC+ at Citizen’s Bank Park.

Weighted runs created plus is, perhaps, the most complete offensive stat out there. If you haven’t already, I highly recommend reading about it in the FanGraphs Sabermetrics Library. It takes the statistic weighted runs created (wRC) and shows how a player’s wRC compares to league average after adjusting for plate appearances and park effects.

These are the top ten seasons at Citizen’s Bank Park according to wRC+ (min. 225 PA). You can read the full list here.

1. 2021 Bryce Harper (175 wRC+)
2. 2007 Chase Utley (172 wRC+)
3. 2010 Jayson Werth (170 wRC+)
4. 2006 Ryan Howard (158 wRC+)
5. 2004 Bobby Abreu (157 wRC+)
6. 2010 Chase Utley (156 wRC+)
7. 2007 Pat Burrell (154 wRC+)
8. 2005 Pat Burrell (150 wRC+)
9. 2005 Bobby Abreu (144 wRC+)
10. 2006 Chase Utley (144 wRC+)

wRC+ is really the crux of my argument. OPS is the only other significant category that Harper could be leading in by the end of the season (he’s currently at 1.052), and right now he’s still trailing 2006 Ryan Howard (1.078 OPS) and 2007 Chase Utley (1.074 OPS). Presuming Harper has 60 plate appearances left at home this season, he would need a 1.188 OPS in those 60 PA to raise his season-long home OPS up to 1.079. His counting stats are nowhere near the top of the leaderboards right now (in large part due to his time on the injured list), and even by season’s end he’ll still be trailing in home runs, RBIs, runs, hits, etc.

However, wRC+ is a comprehensive enough statistic that simply by being at the top of the wRC+ leaderboard, Bryce Harper’s 2021 season is arguably the greatest in CBP history.

That being said, it’s not an open and shut case. As much as I love wRC+, it isn’t perfect. No statistic is. For one thing, Harper is so close to 2007 Utley that it doesn’t really mean much. The difference between a 175 wRC+ and a 172 wRC+ is negligible. Regardless, even if it’s just on a technicality, wRC+ still says that Harper is having the greatest offensive season in CBP history. And when it comes to a meaningless title like “greatest offensive season in CBP history,” isn’t everything a technicality?

Another argument against wRC+ is that it’s a league-adjusted statistic. One could make a convincing argument that “the greatest offensive season in CBP history” shouldn’t have anything to do with a comparison to the rest of the league’s performance. It should just be about pure offensive excellence at Citizen’s Bank Park, and no one was more excellent than 2007 Chase Utley and his .458 wOBA at home that year. That wOBA isn’t just great, it’s historically great, and it’s significantly better than Harper’s .436 wOBA this season.

But having said that, I think adjusting for league-average performance is necessary in this discussion. Context is everything in baseball. Hitting 50 home runs wouldn’t mean anything if everyone around you was hitting 60. In 2007, the league average wOBA was .331. In 2021 that number is just .314. That means the league average wOBA was 5.14% better in 2007 than it is in 2021, but Utley’s 2007 wOBA was only 4.8% better than Harper’s this season.

Update: wOBA isn’t technically “league-adjusted” but it is calculated so that the league-average wOBA will always be close to the league-average OBP. Therefore, if we want to look at a completely ‘unadjusted’ stat, we can use OPS. 2006 Howard and 2007 Utley both had a slightly higher OPS than Harper does this year, but the league-average OPS in 2006 was .768, in 2007 it was .758, and in 2021 it is just .725. That means the league average OPS in 2021 is 4.35% lower than it was in 2007 and 5.6% lower than it was in 2006. Harper’s 2021 OPS at home is only 2.05% lower than 2007 Utley and 2.41% lower than 2006 Howard. In context, Harper is having a better offensive season at Citizen’s Bank Park than either of those greats.

Lastly, one could argue that wRC+ is flawed because it hides the fact that Harper will have missed significant time this season. Even if he plays all 14 remaining home games, he’ll have played in just 71 games at CBP. That means that even if he finishes with the best wRC+, his plain old wRC will almost certainly lag behind 2004 Abreu (73 wRC), 2006 Howard (73 wRC), and 2006 Utley (70 wRC).

The playing time argument is fair, but not too meaningful in my eyes. 71 games is 88% of all home games. That’s still most of the season. Right now, Harper is on pace for 67 wRC at home by the end of the year. That’s within shooting distance of 70 and 73. And finally, if we’re going to penalize Harper for missing time due to injury, we should also give him extra credit for all the games that he played through injury. He had a 74 wRC+ in May while he was dealing with back and wrist issues, and if he’d sat out a few more games that month instead of playing through the pain, his full-season wRC+ would probably be even higher than it is right now.

As I’ve said, Bryce Harper still has fourteen games left to play at home. That’s plenty of time to pad his numbers or plenty of time for him to fall off the pace. It certainly helps that those games will be against the Rockies, Cubs, Orioles, and Pirates. Maintaining a 175 wRC+ won’t be easy, but as it stands right now, we’re watching the most dominant offensive season in Citizen’s Bank Park history.

*Stats as of September 8, 2021