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Is the MLB Moving to a Six-Man Rotation?

By: Mike Patt

Hello sports fans, and welcome back to the IE Sports radio blog. We have made it to the World Series of the 2023 MLB season, and it is shaping up to be a great fight between the Texas Rangers and Arizona Diamondbacks. It has certainly been a fascinating playoffs, the results of which have many pundits questioning the current format. We are in new territory with the league’s current formula and the expansion that has occurred over the past few years. I am not so hasty to question it after such a short trial run. In any case, that is not the question we are here to discuss.

In the latter part of the regular season, notably as rosters expanded to 28 players in September (up from the 26-man limit in place most of the year), I noticed some teams using a six-man starting pitching rotation as opposed to the traditional five-man rotation. This was used to get their top pitchers some extra rest between starts and help keep them fresher down the stretch and into the post-season. With the larger rosters, teams were able to do this without reducing their bullpens, although adding an arm there would help relievers get rest late in the season. Given how important bullpens have become in the playoffs, this is arguably the better move.

This tactic does give rise to a question in my mind. With rosters now slightly larger in the post COVID MLB, and concerns about pitcher health at an all-time high, does the league begin to shift towards a six-man rotation for good? I say begin here because I believe for this to take league-wide effect, the league would have to either expand rosters a little more or make it easier to move relievers back and forth between the minors and majors. However, the benefit of fresher starters later in the season and into the postseason has to be enticing for some teams.

The main downside to this change now would be the loss of a bullpen arm, but I believe there is a way to overcome this problem (in addition to the ideas in the previous paragraph). In a six-man rotation, pitchers would have five games between starts. Depending on how their previous start goes, ie only threw 80 pitches, that starter could be available in certain relief situations for the middle game in that five game stretch. These scenarios could include an extra inning game or a poor start by another pitcher in which the bullpen has to carry 4+ innings. The key here would be not having them make an appearance EVERY middle game, but maybe half the time as needed.

One thing to think about is if the numbers make sense. In a 162 game season, the average pitcher in a five-man rotation will make 32 starts if healthy and pitching at least decently for the whole season. According to studies, the average MLB start lasts about 5.3 innings, but this number includes “bullpen games” where the starter only goes an inning or two and spot starts for rest (no longer needed), so let’s say we get 5.5 innings per start. This would be about 175 innings over the course of the season for most pitchers. Based on this past season, this number looks reasonable.

For this exercise, let’s assume that the average start stays the same, and that the starting pitchers only have to contribute one inning out of the bullpen in half of the games played. This is dealing in rough averages, so you will have to trust my math is correct. With a six-man rotation, each starter would make 27 starts if healthy, and would appear in 13.5 innings of relief. Thanks to the beauty of mathematics, that equates to 162 innings per season for each starter. This formula also saves the bullpen 81 innings over the course of the season, which is equivalent to the one reliever lost in this exchange. And there you have it. Each starting pitcher is saved about 13 innings of wear and tear, and the bullpen does not suffer a net loss. The numbers make sense!

We must acknowledge that, as part of this debate, most teams struggle to field a reasonable five-man rotation, let alone six. This, combined with a consistent injury presence among pitchers, may render this argument pointless. If pitcher freshness and longevity is the goal, then I think teams may at least entertain this idea. Tune in to Let’s Wine About DMV Sports, hosted by Mike Patt, on Fridays at 9PM EST/6PM PST. Be sure to check out all of the awesome shows we have throughout the week, and visit our website Shout out to Planet Jerky for their sponsorship and all you loyal fans that continue to help our network grow. Thank you for reading, and we will see you next time on IE Sports Radio; your direct feed for ALL that is sports.

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