What Will Gonzalez’s Injury Cost The Brewers?

Photo: Jeff Chiu/AP

The Brewers learned yesterday that Alex Gonzalez has a torn ACL, meaning they have lost three regulars (totaling somewhere around five wins) for the rest of the season. In a year that has been almost nothing but bad news, this may be the worst break yet.

The Brewers have already lost Chris Narveson and Mat Gamel, but they will likely be able to recoup most of their value with their replacements: Taylor Green may even end up being a better hitter than Gamel, and Marco Estrada has been competent as fans count the days until the arrival of Wily Peralta. Gonzalez is/was far from the Brewers’ best player, but when it comes to replacing him at shortstop, the Brewers’ in-house options — Cesar Izturis, Edwin Maysonet, and whatever crazy position-change scenario you want to come up with — look sparse and unappealing.

Pretty much every reasonable person would agree with that statement, but today we’re going to try to look at it a little closer. How much were Sea Bass’s bat and glove worth to the Brewers? What will they lose as a result of having to go with Izturis and/or Maysonet? Is the Crew done if they can’t make a trade soon? We’ll try to answer those questions in a little more detail today.

First, we’ll try to estimate what Gonzalez might be expected to produce had he stayed healthy. As far as offense goes, we can do that with Fangraphs’ rest-of-season ZiPS projections. Unaware of his torn ACL, ZiPS expects Gonzalez to hit .246/.286/.399 in his next 426 plate appearances, for a total of 44.4 runs created. Yes, “44.4 runs created” doesn’t mean anything to anyone on its own, but it does work well for comparisons, which is exactly what we want to do here.  

The same system can also be used to look at what might Cesar Izturis and Edwin Maysonet, his current replacements, might do in the same time frame. It’s not pretty: According to ZiPS, Cesar Izturis would produce 18.3 runs in those 426 plate appearances, meaning that the Brewers figure to lose around 11.5 runs at the plate by being forced to go with Izturis. Unfortunately, Maysonet isn’t projected to be much better — substituting him for Izturis only results in an improvement of 1.1 runs, which still makes him almost a full win worse over the rest of the season.

However, Gonzalez wasn’t only signed for his modest hitting ability. He was also regarded as one of the best defensive shortstops in the league. So, we’re going to use some defensive metrics to compare Gonzalez’s fielding with his replacements the same way we did his hitting.

(Note: We’ll be using a three-year average of Ultimate Zone Rating and TotalZone. I’ve said before that I’m not a huge fan of most defensive metrics, but we’re trying to look at everything here in terms of runs, and there’s no other way to do that.)

The zone ratings seem to line up with common belief — the mix of metrics we used has Gonzalez as being worth just over 6 runs per year with the glove. However, it also seems to agree with the belief that Izturis is a premium defender as well, pegging him as only half a run worse per year, on average (5.8 runs versus 6.3 for Sea Bass). Maysonet has only played 20.1 innings of shortstop in the majors, so we can’t really do much with and will have to list him as being exactly average with the glove.

If you total it all up, Izturis and Maysonet are both projected to be around 12-15 runs worse that Gonzalez over the rest of the year. In other words, no matter what arrangement of Izturis and Maysonet the Brewers put at shortstop, they stand to lose a lot of production, probably one or two whole wins. That’s a lot more than the difference between Chris Narveson and Marco Estrada, and way more than the difference between Mat Gamel and Taylor Green. Also, that’s a large win deficit for a team that already has a significant hole to climb out of.

To me, the current void at shortstop is the most pressing need on the Brewers by a gigantic margin, and it needs to be addressed at the trading deadline, or sooner if possible. There are a lot of ways that could be done (fortunately, there are a lot of players that would constitute improvements), and it’s likely that we won’t be able to really discuss the second half of that proposition for a month at least. Until then, we have a problem and no apparent solution in sight.