Amid that wild, wacky flurry of activity that turned over baseball in early and mid-December, the Los Angeles Dodgers remade their infield, swapping out Dee Gordon for Howie Kendrick at second base and trading for Jimmy Rollins to replace the departed Hanley Ramirez. Rolling over the double-play combination of a two-time defending champion is a bold move in silhouette, but Dodgers executives Andrew Friedman and Farhan Zaidi didn’t build that middle infield, and clearly, they didn’t feel much allegiance to it. Rollins is a big-name addition, though his actual value has matched the hype only intermittently throughout his career. He’s been impressively adaptive as a hitter, changing from a high-contact, high-BABIP slasher to more of a modest power hitter as age has dictated. I noticed something, though, that made me wonder about Rollins’s prognosis, even on the short term that is his one remaining season under contract: Two seasons ago, his power went out.

After more than a decade of solid power output, Rollins simply stopped hitting the ball hard in 2013. He hit only six home runs, in a full season of work.

These kinds of outages, I found, are remarkably rare. I checked players ages 32-35, going back to 1988, and only found two examples of players like Rollins, who lost their power altogether in a healthy season after hitting for power for their whole career until that point. They were Ryne Sandberg, whose ISO plunged at age 33, in 1993, but who recovered nicely from there through the end of his career; and Keith Moreland, who hit the wall with the 1988 Padres, at age 34, and was out of baseball by the end of 1989. It’s encouraging that Rollins bounced back from his sudden deflation. Sandberg’s peculiar late-career personal situation makes him hard to use as a baseline, but it feels as though Rollins should have at least one more solid season in him. I liked the deal for the Dodgers right away, and with this small amount of investigative work done, I like it even a little more.

Funnily enough, one season after Rollins had one of those extraordinarily rare power-outage events, the same fate befell Alex Rios:

This is a slightly different case, though. Rios has a couple of other dips in power on his track record, and the drop this season was actually less drastic than the others I’ve isolated. What’s interesting about Rios’s power drop-off is that it came almost entirely in the form of lost home runs. He only hit four (four!) for the Texas Rangers in 2014, in 521 plate appearances. I mention this because Rios signed a one-year, $11-million contract with the Royals in December, and it’s hard to know whether that’s a good deal or not, absent any certainty about whether he can recover his lost slugging ability. While perhaps Rios isn’t in as dire a situation as Rollins was, in terms of sheer power lost, he compares much more closely to Moreland than to Sandberg, if we’re building a profile. Rios, like Moreland, is a large corner outfielder. Rollins, like Sandberg, is a compact middle infielder.

Just for the record, here are Rios’s spray charts for each of the last three seasons. It looks like he stopped hitting the ball as far in 2013, not 2014, so while the timing of his loss of thump can be called a fluke, it looks like a real deterioration. Rios is a decent player, anyway, and it’s not hard to be worth $11 million on the free-agent market anymore, but Royals fans would do well not to expect more from Rios than they just got from Nori Aoki.

Rios might be working against something else, too. It’s well-known that the strike zone has expanded, especially at the bottom, over the past season or three. Operating on the hypothesis that this expansion might particularly damage the ability of tall hitters to access their power, I ran a Play Index query for the number of players in each season to qualify for the batting title while standing at least 74 inches tall and posting an isolated-power figure lower than .125. Here are the top 10 seasons.

Someday when you’re bored, run Play Index queries for a bunch of weird league-wide phenomena. You’ll find that 1981 is always topping the list. It was a strike-halved season, and the half was cut out of the middle, which made for an impossibly strange campaign. Other than that one, though, 2014 is the season on record with the most tall guys fighting power shortages. Ever.

I freely confess that this is unscientific, at best. We’re not comparing leagues of the same size. Players are taller now, so it’s likely that more qualifiers met the height standard than had in previous years, anyway. (I looked it up, and yep: 73 hitters qualified for the batting title at no shorter than 74 inches in 2014, tied for the highest mark ever.) These are real caveats. Still, I think we’re onto something. Jason Heyward, Dexter Fowler, Joe Mauer and Ben Zobrist are all on this list. There are good hitters fighting to find their pop, and the reason might be systemic, not individual. Whether you count that as a strike against Rios, in that it might make him unlikely to rebound, or as a credit to him, in that he’s still hitting fairly well overall, under the circumstances, it should be noted.