How Much Does A Typical Fourth Outfielder Play?

One of the biggest stories heading into the year is how D-backs manager Kirk Gibson plans on juggling his outfield, with a quartet of solid players to rotate in and out in Justin Upton, Chris Young, Jason Kubel, and Gerardo Parra. Many have expressed concern that the so-called "fourth outfielder" - Parra - could get lost in the crowd and not receive as much playing time as his ability merits. However, with three outfielders to fill in for throughout the year, is Parra really going to be buried that heavily? These questions naturally made me look to see how much time a typical fourth outfielder sees for the average team in any given year.

The methods I've used are simple: for National League teams (for whom bench usage is materially different than for AL teams) with at least three regular outfielders - a difficult term to define, which we'll get to - how many games have been played in the outfield by the fourth, fifth, and maybe even sixth outfielders for those teams (min. 20 games played in the OF)? Is it reasonable to expect a fourth outfielder to play 100 games? It it completely unprecedented? Is it commonplace? The answers to these questions have huge implications for the D-backs in 2012, as the good fortunate Arizona had in 2011 with Parra, Young, and Upton each playing over 140 games is a concern that the Kubel addition was meant to address. Is that good fortune fleeting, or could Arizona have reasonably expected it to carry over into 2012 and instead allocated their money elsewhere? Hopefully, these are the questions we'll answer.

Now, as mentioned above, the term "regular outfielder" is something that needs to be addressed. It can't simply be the three outfielders with the highest number of games played, as that doesn't account for the fact that some outfielders slated for regular duty get hurt for extended periods of time, pressing fourth outfielders into extended duty. Since this extended fourth outfielder duty is exactly what we want to measure, it wouldn't make sense to include it in the "regular outfielder" sample. Further, this method is susceptible to errors made due to to rental players. For instance, I wouldn't want to include Carlos Beltran's playing time for San Francisco in 2011 as part of the fourth outfielder sample.

Additionally, using the Opening Day outfield alignment doesn't consider the fact that regular players could start the season on the DL before joining the team at a later date and getting the lion's share of the playing time. That would possibly skew the data such that the role of the fourth outfielder is exaggerated. To dismiss one final idea, using the most highly-paid outfielders as the three "regular outfielders" has an obvious flaw, as Xavier Nady would have been Arizona's third "regular outfielder" in 2011 under this criterion rather than Parra (or any pre-arbitration minimum-salary everyday player).

Because of this, the method is going to have to be somewhat subjective. The Opening Day alignment will be heavily considered, but obvious injury cases will also be factored in as I see them to try and make sure the sample is reasonable. Additionally, mid-season rental player acquisitions will be taken out of the fourth outfielder sample to the best of my ability. I doubt the sample will be perfect, but I am fairly confident that it will be better than using any of the un-adjusted objective methods mentioned above.

With that in mind, here's an vintage Dan Strittmatter Enormous Table (TM).

* Giants acquired rental outfielders Cody Ross, Jose Guillen, and Pat Burrell in 2010.

* Braves acquired rental outfielders Rick Ankiel and Matt Diaz in 2010.

* Braves acquired rental outfielders Nate McLouth and Ryan Church in 2009.

So, to go back to the title, how much does a typical fourth outfielder play? Answer: A lot. What does it mean? Simple: despite Arizona's incredible fortunes in having Parra, Young, and Upton play an enormous majority of the innings in the outfield a year ago, it was very optimistic to expect the same in 2012, if history is any guide (even if CY is an iron man). Now, to be fair, there are a fair share of issues with this study. The numbers can be affected by all sorts of things - injury, poor performance, roster shuffling - that skew the data one way or another. It's also reliant on a subjective identification of "regular outfielder," which assumes that I'm competent at making such a designation - surely a bold assumption to make!

However, all of those factors do need at least some consideration - much as we hope they perform well, neither Kubel nor Young is guaranteed to perform up to career standards, and Upton and Kubel carry some injury history. As such, the fourth outfielder spot was one that needed addressing for the 2012 season, and signing Jason Kubel was a great way to address that need while adding skills to the club that had previously been lacking - namely, left-handed power. Even if you only look at the average games played for the single most-used non-regular outfielders, 91 is a significant total, with a significant standard deviation of 31. Considering that Parra is one of the best in the business in that role, I would expect him to be on the higher end of that range, and would expect Arizona to still find a way to get him into 120 games or more this season.

The bottom line is quite simple: prior to adding Kubel, this team was taking a huge risk in heading into the season with just three reliable outfielders, particularly with Willie Bloomquist needed at shortstop and Collin Cowgill shipped out in the Trevor Cahill trade. A.J. Pollock and Adam Eaton are nice prospects, and Pollock has started 2012 with a bang, but I wouldn't want either of them anywhere near an everyday MLB job. Adding Kubel has greatly reduced the risk of this team having to endure replacement-level-or-worse performance in an everyday outfield spot, while giving manager Kirk Gibson the ability to mix-and-match skill-sets and lineups as he sees fit based on match-ups.