Miami Marlins' starters to blame for bullpen problems?

Miami Marlins manager Mike Redmond does not like that the recent struggles of the team's pitching staff have been pinned to late-game bullpen issues. As reported by Craig Davis of the Sun-Sentinel, Redmond believes that the Marlins' starters, and particularly their failure to go deep into games, has overworked the pen.

"It's tough to cover those innings when you only get three out of the starter," Redmond said after Monday's 9-2 loss in Hand's latest start. "It's a definitely a concern. You can't roll those [relievers] out there every night. You've got seven guys out there. Our starters need to get us deeper into games, and that takes a little pressure off the bullpen. We haven't been able to do that very well."

There is probably some truth to that. The Marlins pen has worked the fifth-hardest in all of baseball so far this season, pitching 48 2/3 innings thus far. They also have not done well, posting a 3.88 ERA and a 4.33 FIP; that FIP is the eighth-highest in baseball thus far.

Redmond thinks that the starters are taxing the bullpen, and that is why its performance has been poor. But historically, bullpens (particularly individual relievers) are getting taxed less and less as pens become more specialized. In fact, according to The Book: Playing the Percentages in Baseball, relievers as of right now could probably afford to work a few more innings individually.

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You can look and see the results from years past to determine just how well bullpens do. Take last season, for instance. I looked at the ten best bullpens by FanGraphs Wins Above Replacement per 500 innings and examined where they ranked in terms of innings of use. Six of the ten bullpens were among the 11 least used in the game. One was the 17th-most used pen. The other three were in the top 10 in usage, including the first- (Minnesota Twins) and second-most (Colorado Rockies) used bullpens.

Let's examine this going further back. Since the 2009 season, the run-scoring environment has trended downwards and stabilized at a decreased level compared to the late 2000's. From 2009 to 2013, I looked at the bullpens that were the best and worst in the game over that span. There was very little in the way of trends towards the ranking of those bullpen's usage rates and innings and how they correlated with performance, at least according to FanGraphs' WAR methodology. The most effective bullpen in that time period was the Chicago White Sox, with 5.8 wins per 500 innings. Of the top 10 most effective bullpens, five were ranked in the bottom 10 in usage, four were in the middle 10, and the most used pen was also ranked (again, the Rockies).

At the bottom of the list was the Houston Astros at a win below replacement level per 500 innings. They were the 11th most heavily used bullpen in the league. Of the bottom ten in effectiveness, three were in the bottom ten in usage, while three were in the top ten. Overall, the average innings pitched rank for the top ten bullpens in effectiveness was 17.9, while the average rank for pens in the bottom ten in effectiveness was 16.8. There is hardly a difference there.

There is also a confounding factor playing into all of this: the quality of the teams involved. The top ten teams in bullpen effectiveness had an average win total of 85.7 wins per season. The bottom ten in relief effectiveness averaged just 77.2 wins per season. In other words, naturally the teams with the weakest bullpens probably had worse teams overall, and vice versa. Yet despite that factor influencing the rankings, bullpen workload barely differed between the best and worst in effectiveness.

Finally, Redmond has contributed in part to this as well. He complained about overworking his relief corps, yet he pitched his best reliever, Steve Cishek, only one inning last week. Maybe if he has Cishek and the rest of the corps contribute more evenly and a little further outside their traditional roles, the team could have avoided overworking one or two relievers during that time period.

The point is that Miami's bullpen struggles are probably a completely random event in the early part of the season. Seven guys (six if you're not counting Cishek during a losing streak!) can have good or bad weeks, and those weeks are magnified in the early season when there is very little precedent or sample size behind them. There is nothing to panic about, and the pen will be what it will be this year. It's hard to tell if it will be a strength like last year or a weakness like 2012, but there is no reason to place particular blame on the starters in this case.