Ahead of the Wild Card Game between the Chicago Cubs and the Pittsburgh Pirates, much of analysis in between the announcement of the starting lineups was focused on the potential trade-off of offense for defense by the Pirates and vice versa for the Cubs. Clint Hurdle chose to start Sean Rodriguez instead of defensive liability Pedro Alvarez at first base. Joe Maddon chose to put Kyle Schwarber in right field and Kris Bryant in left field. Although the Cubs got the win, both moves were reasonable. In hindsight, the move by Maddon was not a big departure from normality, but whether the same justifications exist in the upcoming series against the Cardinals is debatable.

Putting third baseman Kris Bryant out in left field and inserting Tommy La Stella at third base was the biggest surprise about the Cubs lineup against the Pirates, but that position shift as well as others made a bit earlier in the year, put the Cubs defense out of position on almost every position in the field. Catcher Miguel Montero, first baseman Anthony Rizzo, and center fielder Dexter Fowler were in their typical everyday positions, but the other five players were playing at positions other than their typical 2015 setup. The chart below shows the percentage of innings each player played at the position where they started in the Wild Card game.

Percentage of Innings at Wild Card Position in 2015 WC Position Defensive Innings at WC Position Total Defensive Innings % of Innings at WC Position Kris Bryant LF 39 1313.1 3.0% Kyle Schwarber RF 14 445.2 3.1% Starlin Castro 2B 258 1201 21.5% Tommy La Stella 3B 52 140 37.1% Addison Russell SS 471.1 1217.1 38.7%

The least surprising move from above was Addison Russell at shortstop and Starlin Castro at second base. When Russell first came up, Maddon was reluctant to unseat incumbent shortstop and long-time Cub Starling Castro. Castro’s poor play coupled with Russell’s natural position at short eventually resulted in the change towards the beginning of August. Castro at second was not as sure of a thing two months ago, having been benched for a combination of Chris Coghlan and Tommy La Stella. Castro eventually earned back a starting job at second base. Castro has been a slightly below average shortstop, although range has never been his problem. Against Pittsburgh, Castro handled the most difficult part of the transition to second base, turning a key double play with the runner bearing down in the sixth inning.

The last time the Cubs played against Gerrit Cole, left-handed Tommy La Stella was in the lineup at second base. With Castro there, Maddon’s options became relatively simple: Leave Bryant at third, put Kyle Schwarber in left field where he started 15 of the last 22 games of the regular season, and put one of three players (left-handed Chris Coghlan, right-handed Jorge Soler, right-handed Austin Jackson) in right field, OR keep La Stella in the lineup at third, shifting Bryant to left field and Schwarber to right field. There were multiple moves involved, but it came down to La Stella vs a regular right fielder. Maddon chose La Stella.

Moving Kris Bryant to left field seemed like a radical move, but Bryant does have experience in the outfield, and with a pitcher like Jake Arrieta, the move is less of a gamble than it might be otherwise. Arrieta’s 22.8% fly ball percentage is the fourth-lowest fly ball percentage in baseball, and even that number overstates the chances of a fly ball. Dividing fly balls by total plate appearances reveals the following chart among qualified pitchers this season (23.2% is average).

Arrieta along with the Pirates offense, which had the fifth-lowest fly ball percentage in MLB this season, presented a good opportunity to sacrifice defense in the outfield. The move was not without risks. Pittsburgh is a spacious park, and only the Giants had a lower park factor for home runs this season. The St. Louis Cardinals present some of the same opportunities, but without Arrieta, the decision is not as clear-cut.

The Cardinals, like the Pirates play in a pitcher’s park where it is difficult to hit home runs. The Cardinals fly ball percentage is higher than the Pirates, but it is still in the bottom third of MLB teams. The Cardinals strikeout percentage is in the middle of the pack, and with a low home run rate, they tend to put the ball in play. In terms of risking a misplay, the Cardinals look to have a team of gap to gap hitters who could take advantage of misplays in the outfield. No National League team had a greater percentage of their hits go for doubles or triples.

The pitcher also plays a role in the kind of defense a team would prefer to have backing him. Game 2 starter Jon Lester allows more fly balls than Arrieta, but his FB/PA% is still below the mean at 19.4% while Game 3 starter Kyle Hendricks is even lower at 18.5% this season. With the Cardinals starting left-handed Jaime Garcia, the Cubs are less likely to insert La Stella, perhaps even Schwarber, into the lineup so no defensive sacrifices will be necessary.

Against John Lackey, there might be extra incentive to try and get an extra left-handed bat in the game, whether that means putting La Stella at second and Coghlan in right or keeping the lineup the same as the one they used against the Pirates. Over the last four years, Lackey’s FIP is roughly half a run higher against lefties–he has a 23% K-rate and 4% walk-rate against righties and a 17% K-rate and 7% walk-rate against lefties.

Maddon’s decisions seem almost trivial in hindsight given how great Arrieta is pitching, but Maddon will now be faced with slightly more difficult decisions against the Cardinals. Against a different team with different pitchers on the mound, the calculus changes a little. The expected benefit is not quite as great, and the risks, although minimized without Gerrit Cole on the opposition, are slightly greater given the makeup of the Cardinals. Minor changes are not likely to make a difference in a game and the discussed changes are defensible regardless of the decision, but if the ball hits the right spot and a game’s outcome turns on that decision, the second-guessing will fierce, even if it is not entirely fair.