Do you know what bullpen coaches do? I will be honest with you: I was a baseball fan for a long time before I learned that bullpen coaches exist and are different from bullpen catchers. (They both start with "C"!) It was even later that I learned that bullpen coaches are not merely functionaries employed to answer the phone when the pitching coach gets lonely and/or bored.
Here is what Wikipedia claims:
The bullpen coach is similar to a pitching coach, but works primarily with relief pitchers in the bullpen.
Here is what the Baseball-Reference Bullpen says:
[T]he bullpen coach works with the team's relief pitchers, ensures that they are ready to enter the game and supervises their warm-up.
(The shocking lack of serial comma threatens to undermine the Bullpen's entire argument, but I think we all just have to breathe and get over it.)
Not every bullpen coach merely works with pitchers, however: This Alyson Footer piece from 2010 noted that Jamie Quirk, then the bullpen coach in Houston and these days the bench coach for the Cubs, "has worked extensively with the two starting [catcher] hopefuls" and "spends the majority of time with the catchers during Spring Training" but has "plenty of face time with the pitchers" during the regular season. (This has been a presentation of Zagat Prospectus.)
One begins to suspect that different teams have their bullpen coaches perform different jobs, particularly since some, like the 2010 Astros noted above, have catchers doing the job, while others, like the 2013 White Sox, hire ex-major-league relief pitchers who once held the single-season saves record to serve in the role.
So that, to the extent that we can make any general statements, is what the bullpen coach is. But who is the bullpen coach? Relying on this list of major-league coaches, I gathered some data and here present it that you may learn and be contented.
Fewer bullpen coaches than you might suppose played in the major leagues. Is that presumptuous? Maybe it's better to say that fewer bullpen coaches than I supposed played in the major leagues. Of the current group of 30, just 19 had at least a cup of coffee in the bigs.
Two of those 19, however, stopped with that one beverage. One was Bobby Cuellar, currently of Minnesota, who threw four games in relief for Texas in 1977 and never sniffed the majors again despite being just 24 at the time and further despite pitching four more or less complete seasons at Triple-A from 1978 to 1981. The other was Blaise Ilsley, who made 10 relief appearances for the 1994 Cubs in his 10th year in professional ball.
Ilsley, by the way, does not win the award for Most Interesting Name, Major League Bullpen Coach Division. That prize goes to Euclides Rojas, with Reid Cornelius and Glenn Sherlock also in the mix along with Ilsley. (FACTS NOW: Euclides was a rival of Socrates, Reid Cornelius is actually a wealthy 19th century industrialist come back as a coach, and Glenn Sherlock still hasn't caught that bastard Glen Moriarity.)
Another way to look at this is that of the 30 bullpen coaches, just 17 had even arguably substantial major-league careers. And frankly, that 17 is being quite generous to Jim Wright (75 2/3 innings in 24 games) and the aforementioned Cornelius (211 innings in 45 games). Without getting into fine definitional details, then, we can just say that approximately more or less halfish of major-league bullpen coaches had major-league careers.
Obviously the 15 or 13 or 11 bullpen coaches who did not have careers in the majors were not very good at baseball compared to the population of major-league baseball players. (Though note that none of them is like an MLB version of Lawrence Frank, the NBA coach who didn't even play college ball, much less professionally, by which I mean that every one of the bullpen coaches played professional ball in the United States. That includes Euclides Rojas, a fascinating case: he was a Cuban relief star before defecting, but he managed just 79 innings across two American minor-league seasons before becoming a coach at the age of 29. Anyway, the point is that the worst of these bench coaches was far, far better at throwing and hitting and fielding than you and I were. (Except you, Mr. Beane. Thanks for reading, by the way.))
Even considering only the major leaguers, though, does not yield a group laden with All-Stars. The bullpen coach with the most career WARP is Dennis Martinez (22.7), and it's not even close. Numbers two and three are Mark Gardner and Jaime Navarro with 9.1 and 8.8 respectively. The total career WARP for the 17 pitchers of the 19 players (more on the other two later) is 61.9. That's basically Curt Schilling's career (60.9), though I would note that he required about one-fifth as many innings to get there as our bullpen coach population (3,261 to 15,604 2/3). Some context for that: the number of innings our coaches used to rack up one WARP (252) is a tad worse than Joel Pineiro's career ratio (7.5 WARP in 1,754 1/3 innings, or one WARP every 234 innings).
Having said all those things, I almost feel like I'm denigrating Dennis Martinez, who threw a perfect game, made four All-Star teams, and received Cy Young votes twice. He doesn't belong in this group. Hopefully he'll advance to pitching coach soon, where he can join such luminaries as Rick Honeycutt, Curt Young, and Doug Brocail. His true peers.
The short version, though, and excluding El Presidente, is that big-time major leaguers aren't bullpen coaches.
Seven of the 17 major-league pitchers in the bullpen coaching group threw over 70 percent of their big-league games as starters. "Seven out of 17" isn't that great a number, sure, but given that the word "bullpen" is in the name of the job and that a bullpen coach's duty station is, uh, the bullpen, you might think that someone who didn't make his professional home there as a player might not be as well-suited for the job as some other candidate. It's not like there is a shortage of ex-bullpenners to choose from, after all.
I don't want to be dramatic, though. You don't have to do something a thousand times before you teach it, and, as discussed above, a bullpen coach's responsibilities include a variety of tasks, many of which are not unique to the bullpen.
I said I'd deal with the non-pitchers. I don't make empty promises.
Two of the 19 major-league players who are currently bullpen coaches spent their careers as backup catchers: Kevin Cash and Eddie Perez. It is not immediately obvious that this should be unusual. Catchers, after all, are frequently transmogrified into bench coaches and managers, and while bullpen coach isn't directly on the path to manager, someone who wants to manage is probably better off being a bullpen coach than not coaching at all. Further, outside of an ex-pitcher, who better than a catcher to coach a pitcher's mechanics, game preparation, pitch sequence, and mental approach?
No, what's unusual about Perez and Cash is that they were major-league catchers. Remember: Of the 19 bullpen coaches who played in the majors, 17 were pitchers. Of the 11 bullpen coaches who only appeared in the minors, by contrast, just three played exclusively on the mound.
Maybe it's just a small sample. Maybe if I went about this comprehensively, if that's even possible, and gathered the list of all the people in the last decade or two decades or seven decades who were bullpen coaches (were there bullpen coaches in 1942?), I'd find some equilibrium of pitchers and catchers that didn't actually vary based on whether the coach had played in the majors.
Or maybe not! Maybe there's really something about being a major-league catcher that makes you more suited to jump into bench-coaching or minor-league managing, to starting right in on the rat-race track to one of the 30 big-league managing jobs. I don't know.
What I do know is that, compared to the 17 big-league pitchers and two big-league catchers who make up one segment of the bullpen coach population, the remaining 11 are a much more mixed bag. You noted how I said "just three played exclusively on the mound" above, right? That's because Stan Boroski, Tampa Bay's bullpen coach, both pitched and caught in the minors. That's pretty neat! He's got both perspectives.
Then there's Jim Lett of Washington and Darren Bush in Oakland. Lett is the oldest current bullpen coach, at 61. Bush is the second-youngest. He's 38. What do they have in common, these dudes who could be father and son? Lett played third base and Bush was mainly an outfielder. Third basemen and outfielders are not catchers. They are not pitchers. Outfielders in particular tend to stand very far away from the whole pitcher-catcher situation. Third basemen generally have to pay too much attention to the batter and whether a screaming line drive is going to take off their heads to really monitor a pitcher's mechanics.
Now, to be entirely fair, Bush did catch a little, but he's not really a catcher; he played in the outfield for three years in independent ball (though he did get two games at catcher in 1998), came into the Cal League in the San Diego system as an outfielder in 1999, played 30 of 109 games at catcher in 2000, then went back to the outfield in 2001 in the Florida State League for Philadelphia. He's not a catcher.
Lett is less complicated, by the way. He had more appearances at pitcher (one inning) and shortstop (one) than he did behind the plate.
Also, Lett and Bush are similar in that they did not come up through the coaching ranks as pitching coaches or instructors. (Which makes sense! They weren't pitchers or catchers, so why would they be pitching coaches in Triple-A?) Bush has been a coach in the minors for 10 years, eight of which were spent as a manager. (The other two were in a stint as hitting coach in Stockton.) Lett managed for nine seasons from 1977 to 1985 and has spent five seasons as a major-league bench coach. He has also been a minor-league field coordinator and assistant director of player development.
Without much actual insight into the A's and Nationals' approaches to coaching or the skill-sets of Bush and Lett, one might posit that the teams value having the men around more for their general coaching acumen, calming influence (or energizing influence, either way), strategic planning skills, and organizational capabilities (e.g. in setting up spring training or in-season schedules) than their mastery of pitching mechanics and the art of throwing the cutter. Or maybe the Nationals and A's structure their coaching in such a way that a second pitching coach would cause confusion or difficulty. (For what it's worth, neither team is part of the growing movement of teams with two hitting coaches.) Or maybe Bush and Lett are actually weird pitching savants who fit the "if you can't do, teach" model.
As to Bush, at least, there may be an element of the organization wanting to give him exposure to different aspects of coaching because he's viewed as a potential big-league manager. Bob Melvin is great, but he's 13 years older than Bush, no manager sticks around forever, and the A's have promoted from within before (Ken Macha and Bob Geren were both bench coaches before they were managers, and Geren was Sacramento's manager before he was bench coach). With so many years of minor-league managing under his belt, the A's might feel that he's better off learning the major-league game and atmosphere as the next step along the path to managing, especially since he didn't play in the majors, even if that learning takes place as a bullpen coach rather than in the dugout.
So: did you learn something?