If there is a “Team Rondon” out there pulling for this guy to get the Tigers closer job, I am not on that team.
What I look for in any reliever that’s going to get a defined-inning role is control. There are two sensible reasons why:
The first is that defined-inning guys are going to be called upon to pitch multiple days in a row. If you keep missing the plate, you’re going to throw a lot of pitches and have a hard time getting three saves on three consecutive days without your arm falling off. Bruce Rondon obviously has good stuff, but he was unable to get through his assigned inning this afternoon after throwing 22 pitches to four batters (two of whom walked, the other two of whom struck out). A guy that needs a lot of pitches to get through an inning should either be expected to get a day or two off in between appearances OR have a less-than-an-inning role. Al Alburquerque did a phenomenal job in just such a role for the Tigers in 2011 – it isn’t that he never threw an inning or more, it was that his job was to come in with men on and get the K. If you bring him in in a tie game with a runners on second and third with one out – do you care if he walks one of the three guys he faces? Not a lot – you’re mostly concerned about what happens to the two guys he inherited. Rondon looks like he could do good work in that type of a role too – but things that don’t matter much in those situations DO matter a lot when you get the luxury of starting an inning with the bases empty (and vice versa).
That brings me to the second reason – that a lack of control and/or command is going to get a guy into trouble eventually. If you inherit an empty base with RISP, a walk isn’t anywhere near as dangerous as a single. If the bases are empty, they’re exactly the same thing – and the second walk of the inning is nearly as bad for you as the second single. A walk-prone reliever is going to put themselves in a lot of dangerous positions and on occasion it will blow up in their face (unless they walk 15 per 9 and keep a 0% HR/FB rate like Al Al in 2011). Most relievers have pretty good stuff – since they don’t have to rely on their worst pitches like a starter does and because hitters never have a chance to figure them out. Many are virtually unhittable when they are “on”, but even the others are hard to hit when they are “on”. We’re mostly concerned, when deciding which reliever we want on the roster, with how often they will be “off” and just how bad they will look when they are.
If – at the best of times – you miss the plate a lot, your terrible hanging changeup that gets drilled into the gap for a double might score two runs. If you don’t, that same terrible hanging changeup is much more likely to just put a runner on second. The home runs you’ll give up will be solo shots and not game-changers. Joaquin Benoit was “off” in the second half of 2012… on June 29 he had allowed 1 home run and a 1.80 ERA. From June 30 on he allowed 13 home runs in 36 innings (which is atrocious by any standard) but was somehow able to limit that damage to a 5.25 ERA, 3 blown saves and a -0.287 WPA. 10 of those 13 home runs were solo shots and he only allowed 2 runs to score during that span without the aid of a home run – in large part thanks to the fact that he walked only 2 batters per 9 innings over that span. That’s why the reliably good relievers tend to walk very few batters – this shouldn’t surprise anyone. The argument that walks are not a big deal for relievers because walks don’t matter much in high leverage situations doesn’t hold water. Walks don’t matter much (relative to hits) with RISP and strikeouts do matter more with RISP, but that sort of high-leverage situation has little relation to a high-leverage inning. There are certainly closers that have had great seasons while walking 4 or 4.5 batters per 9 innings – like Valverde in 2011 – though there are more that have done as well with fewer. However, what we’re talking about with Rondon or Alburquerque as a closer would be a walk rate in the mid-5′s.
There have been 119 “qualified” seasons from relievers over the past decade with walk rates that high, and a handful of them have been really good (and some others have been really lucky) like Carlos Marmol in 2010. But, none of them have managed 40 saves and Marmol is the only one to put up more than 1.3 WAR in a single season. The median WAR for qualified relievers with walk rates above 5 – and remember that they had to be doing a lot of other things right to get put in enough games to become “qualified” – is ZERO, despite a median strikeout rate over 8. We also – due to sheer coincidence – had 119 qualified reliever seasons over the past decade with walk rates under 2. Of those seasons, 54 produced more than 1.3 WAR (not ONE). Median WAR was 1.3 – as compared to zero. Median ERA was 2.89 and Median xFIP was 3.52 – as compared to 4.30 and 4.80 for the high-walk group – despite the fact that the median strikeout rate for the low-walk group was lower than for the high-walk group. The low-walk group also produced 17 seasons with 40 or more saves.