It's pretty standard for Royals fans to spend Spring Training looking for success stories among the young, up-and-comers. Guys who wouldn't draw any interest from other fanbases become hot topics of debate in Kansas City. I'm old enough to remember when the internet was awash with spilled ink and the blood of expectations because of one Johnny Giavotella. Johnny was never a top prospect*, even among the Royals. But fans demanded he be promoted with the zeal you might have more reasonably expected from Cubs fans when Kris Bryant was nearing his debut.
*It's a bit irrelevant to the story, but I can't not include that Johnny finally got his shot to start with a mediocre Angels team in 2015 and turned out not to have what it took to be a starter in the big leagues.
There have been plenty of guys that Royals fans have been talking about in 2022. Bobby Witt Jr. was all anyone cared about in Spring Training. Then MJ Melendez, Edward Olivares, and Kyle Isbel began to get opportunities. Fans are still weeping and gnashing their teeth because Nick Pratto and Vinnie Pasquantino are relegated to continue playing for the Omaha Stormchasers when it's readily apparent that there is nothing left for them to prove there. One guy that no one has talked about is Emmanuel Rivera.
Rivera has never been considered much of a prospect. He's never made a top-100 list. He's never been near the top of the Royals' top prospect lists, either. FanGraphs considered him to have a Future Value of 40; on a scale of 20-80, he is expected to be a full standard deviation below major league average. While the Royals searched for competent play at third base last season, he got a cup of coffee in the big leagues and didn't really wow anyone, either. In 29 games, he managed only a single home run on his way to an 80 wRC+ (Meaning he was a 20% below league average hitter) and played mediocre defense while not seeming very fast. He did steal a pair of bases for whatever that's worth. There wasn't much to suggest he was having bad luck, either -he had a .324 BABIP.
Something seems to have changed this season, though. Despite a woeful .233 BABIP, he has a 120 wRC+ after 21 games. He's been hitting so well that with Nicky Lopez struggling and Adalberto Mondesi on the IL for likely the entire season, he's quietly grabbed a spot in the starting lineup while no one was looking.
Rivera is walking and striking out at slightly lower rates, but nothing to write home about. Somehow his Isolated Power has skyrocketed from a Nicky Lopez-esque .078 to a George Springer-like .259. The question becomes, naturally, how did he do that? Well, he didn't do it by changing his launch angle - he's hitting fewer line drives and more groundballs this year. He also didn't do it by increasing his average exit velocity - it's almost exactly the same. He seems to have done by hitting more balls nearer his average than ever; he converted half of his soft-hit balls from last season into medium-hit balls this year. He's also making significantly better contact with the ball. In two-thirds of the batted ball events he had last year, he has barreled the ball five times already despite only barreling it once last season.
Looking at videos of his swings from last year and this year, it's hard to see any significant difference. He might be holding his bat slightly lower, but the stance looks remarkably similar. His plate discipline numbers are also the opposite of what you might expect; he's swinging far more often at pitches outside the zone before and making contact a lot more often, too. Overall, his called strike and swinging strike rates are very similar to last year, so it would seem he's fouling more balls off. Does that mean he's forcing pitchers to give him pitches he can handle? Maybe!
Another set of numbers I like to look at to help judge if a player has been lucky or not are his Weighted On-Base Average (WOBA) and eXpected Weighted On-Base Average (xWOBA.) The first stat tells you how often a player has gotten on base but weights extra-base hits more heavily; generally speaking, a .300 WOBA is considered reasonably good. The second does the same thing but based on what would be expected given batted ball data. If a player's xWOBA is lower than their WOBA, it's usually safe to assume they've been getting a bit lucky and vice versa. Rivera not only has a .333 WOBA, which is pretty good but a .420 xWOBA which suggests this isn't even all that he's capable of.
It seems like there's plenty of reason to think Emmanuel Rivera is the real deal and could be even better with slightly better luck or some tweaks to his batted ball profile to get the ball in the air and off the ground more often. At age 25, he's also got plenty of good years ahead of him. If these are the kinds of results we can expect from working with Alex Zumwault and Mike Tosar (who would have worked with him while he was in the minors before all of their promotions), then there might yet be hope for the future of the Royals offense.
Now, if only they could figure out what to do about the pitching...