Jon Jay, Peter Bourjos and playing time in center field

After acquiring Peter Bourjos from the Angels along with Randall Grichuk for David Freese and Fernando Salas, many assumed Bourjos would be given the inside track to become the de facto centerfielder for the Cardinals. Coming off a poor season defensively and some untimely gaffes in the playoffs last year, Jon Jay looked to be sacrificing a lot of playing time in 2014. Early on, Bourjos received a majority of the starts, but with Jay picking things up offensively and Bourjos struggling out of the gate, Jay has received five out of the last nine starts plus an additional start in right field.

Before the season, Mike Matheny appeared to be paying at least lip service to the idea that Jay could win the starting job. During the first ten games of the season Peter Bourjos received eight starts confirming the assumed pecking order. After 19 games, here is where the players stand for playing time.

While Jay has received more playing time as of late, Bourjos still has more starts in centerfield and more starts overall. Playing twenty games in twenty days is more likely to benefit Jay. With Matt Holliday and Allen Craig figuring to receive an occasional day off, Jay is in prime position to receive starts in right field while the primary starters rest. Last season, Jay received almost all the starts in centerfield, making 141 starts and playing 152 games at the position. As a result, he ended up making 137 plate appearances against lefthanded pitchers where he hit just .220/.306/.314 for a wOBA of .282. He's likely not that bad against lefthanders, given a career slash line of .270/.343/.346, but he is still not a strong hitter against lefties. With Bourjos coming aboard, there is little reason for Jay to hit on the wrong side of the platoon. Here are the starts so far this season based on the handedness of the pitcher.

Peter Bourjos has received all of the starts against lefthanded pitchers while the starts have been split evenly against righties. Jay has also received an additional two starts against righthanders in right field while Bourjos remained in center. While Jay is not likely to keep up his current line of .297/.350/.486 and .358 wOBA, particularly in the power deparant, his career line against righthanders, .300/.360/.420 and .342 wOBA, is a reasonable expectation for Jay this season.

Bourjos has struggled offensively this season, hitting just .190/.261/.310, but has a career .250/.305/.395 slash line and wRC+ of 95 that is more in line with what can be expected going forward. Combining that production with superlative defense in centerfield, the Cardinals have two above average centerfielders. Deploying them based on opposing starter is one way to dole out starts, but it is also possible to start the players based on the Cardinals' pitcher starting the game. Below are the starts by Jay and Bourjos based on starter.

Bourjos has started every one of Wacha and Miller's starts. Not coincidentally, those pitchers have the highest career fly ball percentage. The only start Jay did not make for Wainwright was opening day this season. The two starts Jay has received this season in right field were both made when Shelby Miller was the starter. Given Miller's fly ball tendencies putting Jay's above average range in a corner spot relative to Allen Craig is a solid decision when deciding to give Holliday or Craig the day off.

These differences are not likely to make a significant impact, but over the course of a long season, gaining small advantages could be meaningful in a potentially tight race for a playoff spot or division title. While Matheny's in-game tactics have been somewhat frustrating to start the season, this type of decision-making, if continued, shows how advanced statistics can positively help on-field decisions. Perhaps that is making a little much of the apparent patterns less than twenty games into a season, but these starts do not appear coincidental. Both centerfielders should see plenty of playing time as the Cardinals look to maximize performance from the position as the year goes on.