The big move for the Cubs this winter was signing free agent shortstop Dansby Swanson to a seven-year deal. But signing Cody Bellinger to a one-year contract to play center field might be the most impactful defensive move in MLB this offseason.

The Cubs played eight different players in center field last year, with 98% of the innings played by five players – Christopher Morel, Rafael Ortega, Nelson Velázquez, Jason Heyward, and Michael Hermosillo.

In all, those eight combined for -19 Defensive Runs Saved, which was the worst for any center field group in MLB last season. It was the fourth straight season in which the Cubs had a negative Defensive Runs Saved in center field.

Each of the five primary center fielders in 2022 had a negative Runs Saved, with Velasquez (-6 in 198 innings) and Morel (-5 in 458 innings) as the two with the worst numbers.

Cubs center fielders failed to make 37 plays on which their out probability was at least 50%. There was this and this and this and this. There were a combination of late breaks, tough looks at the Wrigley Field sun, hesistancy, failed dives, and balls that were just missed.

Bellinger was brought in to stabilize the position. He saved 15 runs in a little more than 1,000 innings with his center field defense from 2017 to 2020. The last two seasons, he’s slipped. He’s at -1 Runs Saved in just under 1,900 innings in that time.

But even so, that’s a huge upgrade from what the Cubs had last season.

The chart below compares Bellinger’s performance in center field to that of the Cubs in 2022.

The out rates are defined as the number of times a play was successfully made by Bellinger or the Cubs against a batted ball on which the out probability was greater than 0% (the number of opportunities are in parentheses). Bellinger, was better than Cubs center fielders at making plays in all areas of the field.

Think of Plays Saved here as similar to Statcast’s Outs Above Average (we’ve tracked Plays Saved back to 2003).  Bellinger made just about as many plays as he was expected to make in center field last season. Cubs center fielders made 18 fewer than expected.

However, one thing to keep in mind is that Bellinger could play up to 81 games a year at Dodger Stadium, which plays much differently than Wrigley Field, where the combination of wind and recently installed video boards make playing the outfield a huge challenge. Bellinger has played only six career games in center field in Wrigley (we didn’t notice anything particularly eventful for him in them other than the wind knocking down a few balls that he caught).

We’ll be learning as he does whether he can handle the position at a high level. The challenges, particularly the wind, will be plenty.

“It’s just so impactful at Wrigley,” Cubs left fielder Ian Happ said of the wind on The Sports Info Solutions Baseball Podcast last year. “When we come to the park every day, one of the first things we do is look at which way the flags are blowing. Because Wrigley Field is such an old stadium, it’s so low as far as where that second deck (of stands) is. And it is so open to the elements because the outfield bleachers are so low.

“You think of Yankee Stadium as a massive cathedral where no wind can possibly get in. At Wrigley Field, it’s open air and the wind has an impact on the flight of the baseballs like nowhere else because it whips right off the lake. We’re looking at balls hit 108 MPH at 25 degrees that aren’t going out of the park one day, then balls hit at 92 and 35 that might go out of the park on another day. It’s an interesting field to play it because it can play so totally different every day.”

The Cubs have placed an emphasis on up-the-middle defense this offseason, adding Swanson, Bellinger, and catcher Tucker Barnhart, and moving standout defender Nico Hoerner from shortstop to second base. If Bellinger can manage Wrigley’s elements and just be what he was defensively there in Los Angeles, he could notably impact the team’s win total for 2023.