When the Kansas City Royals called Salvador Perez to the big leagues in August 2011, there was little fanfare. At the time, he was an unheralded prospect. He wasn’t a total nobody, but take a look back at pre-season system rankings and you won’t find his name near the top spots. John Sickels at Minor League Ball listed Perez as the Royals’ 18th-best prospect in January 2011 and gave him a ‘C+’ grade. Sickels defined a ‘C’ prospect as
the most common type. These are guys who have something positive going for them, but who may have a question mark or three, or who are just too far away from the majors to get an accurate feel for. A few Grade C guys, especially at the lower levels, do develop into stars. Many end up as role players or bench guys. Some don’t make it at all.
Sickels ranked Perez behind such stalwart Major League Baseball stars as Brett Eibner, Tim Melville, and Chris Dwyer. In fairness to Sickels, and to every other prospect writer, there was no reason at the time to much believe in Perez. The Venezuelan entering his age-21 season had just turned in a perfectly average season at High-A Wilmington. And Perez’s overall production in Double-A Northwest Arkansas and Triple-A Omaha in 2011 weren’t extraordinary. The Royals called him up anyway.
Immediately, Perez showed an offensive aptitude he had never really shown in the minor leagues. In two months in 2011, Perez hit .331/.361/.473, and in half a season after a major injury in 2012 Perez hit .301/.328/.471. In 2013, Perez hit .292/.323/.433, a lower figure but still above average and the first full season he played as a healthy big leaguer.
At the time, we all thought Perez might actually be a good hitter. But as his minor league numbers suggested, it was a mirage. From 2011 to 2013, Perez hit .301/.331/.451, good for an on base plus slugging (OPS) of .782 in 989 plate appearances. Since then, his slash has been a significantly worse .255/.286/.437, an OPS of .722 in 2590 plate appearances. During those years, he never hit .300. Or .290. Or .280. Or .270.
Unfortunately, Perez is never going to be a good hitter. Sure, he may have decent years (like 2017), but he is never going to be a good hitter. That’s because it is essentially impossible to be a good hitter with Perez’s walk rate.
See, on base percentage (OBP) is the lifeblood of offense. You only have 27 outs in a regulation game of baseball, and players that avoid outs at a high rate are simply better offensive players than those that avoid outs at a low rate. It’s that simple. Power is good too, of course, but there’s no limit on how many extra base hits a team smack in one game. There is a limit on how many times the little ‘O’ light brightens on a scoreboard for your team.
The best stats for comparing players are weighted ones like weighted runs created plus (wRC+) or OPS+. Both compare a player’s performance against league average after controlling for park effects. We know that raw numbers mean different things instinctively; a player who hit 50 home runs in a season five years ago is far more impressive than someone who hit 50 in the peak steroid years.
What does this all mean for Perez and his walk rate? Well, it means we can accurately compare Perez’s overall offensive output against thousands of other hitters going back decades and see if Perez can become a good hitter with his walk rate.
If you’ve read the title of this post, you can probably guess the answer, but we’re going to take a look anyways. Since 1995, 22 players have at least 1000 career plate appearances with a walk rate of under 4%. Exactly one of them has a wRC+ of 100 (league average) or more.
Yep! Out of over 1500 players with at least 1000 career PAs during that time, only 22 have a walk rate under 4%. This makes sense, because these guys are simply bad hitters and bad hitters don’t often stick long in the Show.
In order to be an above average hitter with that low a walk rate, you need to be able to do one of two things. Option one is being able to hit for average, getting your OBP that way—this is how Yulieski Gurriel is hitting 6% better than league average, because his batting average is .290. Option two is being able hit for a lot of power, overcoming a lack of OBP through sheer strength. Ryon Healy barely missed this cutoff with a career walk rate of 4% on the nose, but he is an above average hitter (105 wRC+) because he has hit for some serious power in his career with an isolated slugging percentage (ISO) of .197.
These factors hold true for guys who walk a lot more than Perez does, too. Among all hitters with 1000+ PAs since 1995, 92 players have sported a walk rate below 5%. Only six of those players have hit better than league average, and none of those hitters was better than 8% above league average. If you want to hit 10% better than league average or more, the bare minimum walk rate you need is 5%, and ideally you’re going to want 7%.
Perez simply does not hit for enough average nor does he hit for nearly enough power to be a good hitter. Everyone knows that he’s a free swinger, but the core problem with Perez is that he will never be a good hitter until he walks more. I’ll say that again: Perez will never be a good hitter until he walks more.
There are some who will argue that Perez does not need to be a good hitter to provide value, and that is currently true. Perez is an excellent defensive catcher and reliably healthy, both rare and important skills that set him apart from his peers. But if Perez is ever to go the Joe Mauer route and segue into a late-career switch to first base, he’s going to need to hit to provide any value at all.
If Perez isn’t able to walk more, we ought to hope that doesn’t need to happen.