MLB Inception! Who wins baseball's rising pitcher-swap matchups?

During opening weekend, John Ryan Murphy, the Diamondbacks' third-string catcher, faced Brock Stewart, the Dodgers' mop-up reliever. Stewart had the bat.

These ultra-rare matchups -- between a position player pitching and a pitcher hitting -- are peak baseball weirdness, and the frequency of them is creeping upward. There were eight such plate appearances in the entire first decade of this century; then 12 in the first eight years of this decade; then 12 last year alone. There have already been three in the first two weeks of this season.

Greater frequency doesn't strip them of their weirdness, and watching two normies briefly controlling a multibillion-dollar industry is like -- well, actually, what is it like?

That's the question today. If real baseball is like a really good salad, then does Hitter Pitching To Pitcher Hitting just resemble a sloppier, lower-quality salad? Or is it a total inversion, a bowl of globby ranch dressing sprinkled with lettuce shreds? Can you eat it?

Here are three facts:

• Hitters pitching have allowed a .356/.424/.638 slash line since 2017.


• Pitchers hitting have hit .120/.151/.157.


• The league overall has hit .251/.321/.417.

So what's your hypothesis? When the first and second bullet points smash into each other, will they cancel out and look something like league average? Or will hitting pitchers, who at least have more experience at the thing they're terrible at, crush the pitching hitters? Or does the difficulty of hitting a round ball with a round bat simply transcend pitcher quality, so that pitchers hitting will be terrible in all circumstances? Get your bets in. We're going to try to answer the question.

1. Here's infielder Scott Kingery facing lefty reliever Jerry Blevins last year. Blevins had batted three times in his career, hitlessly, until this:

There might not be anything in baseball that intentionally looks less like baseball than a Scott Kingery pitch. He threw 16 pitches in this game -- enough to get through eight batters, on account of how hittable the pitches were -- and not one was hard enough for Statcast to track, so we don't even know how hard he was throwing. Maybe 50 mph? Look at his posture at the moment of contact and tell me he just did sports:

Watching major league batters try to hit 50 mph pitches is a little bit like a thought experiment; but watching Blevins try to hit them is like watching two dudes joking around at the park. A 10-year-old would have hits in the Scott Kingery version of the majors.

Blevins smiles at first base, though. A big smile. He makes sure the ball gets saved, because that's his first major league hit, and you notice he's not making an exception for it being against Kingery. The hitting pitcher wins this round.

2. Here's utility man Cliff Pennington facing reliever Mike Mayers last year. Mayers had never batted in the majors, but in the minors he was 2-for-52 (both singles) with 32 strikeouts -- an .038 batting average.

Pennington is the opposite of Kingery. He averages 88 mph in this outing, harder than a handful of actual major league pitchers. It's a low-spin fastball, straight and not commanded well, so there's no confusing it with, say, Kyle Hendricks' 88 mph fastball. But as we go from Kingery to Pennington, we see the challenge in treating these weird occurrences as merely scaled-down versions of major league baseball. Kingery throws pitches, as we said, a 10-year-old could hit. Pennington could pitch successfully in independent ball. When we talk about pitching hitters facing hitting pitchers, we're not really talking about one kind of weird occurrence here; we're talking about something that encapsulates the entire experience of competitive baseball, from childhood to the pros.

Mayers also smiles a bunch. His smile looks more like a "that other guy got Kingery and I got this?" kind of smile, but he also recognized the farce. He fouled two pitches off, and then he walked. The hitting pitcher wins again, but this one looked more like real baseball.

3. Here's second baseman Daniel Descalso facing starting pitcher Gerrit Cole, who was 0-for-4 with four strikeouts already that day.

The catcher asks Cole something at the start of the at-bat, and Cole shakes his head "no." Did the catcher ask him if he planned to swing? We don't know, but Cole quite emphatically took three consecutive pitches down the middle for strikes one through three.

Cole has three home runs in his career. He's a pretty good hitter, and against Descalso he had the best chance of his career to pad his stats. But he doesn't appear to have put any value whatsoever in stats derived against Descalso (whom he'd struck out twice that game). To keep the sport real, Cole knew he had to walk to the batter's box when it was his turn in the order, but he did not have to go through with the game of trying hard against Daniel Descalso. He forfeited, then he went back out to the mound and completed his shutout, the first and only one of his career. The pitching hitter wins the round.

4. Here's Descalso again, facing starting pitcherGerman Marquez.

Marquez, unlike Cole, is up there looking to do some stats. He swings at the first pitch and hits it nine rows into the stands. Descalso, who would stoically allow a similar home run to Carlos Gonzalez (a hitter) during the same outing, is here very demonstrative. His shoulders sag and he staggers around the mound with a bashful grimace. He watches this home run land; he didn't bother with Gonzalez's.

Marquez's home run probably won him the Silver Slugger Award (for the best hitter at his position) last year. Marquez hit .300/.300/.350 on the season, with that home run his only extra-base hit of the year. Had he faced a real pitcher in that spot, and not hit the home run, his homerless stat line quite likely would have lost to Michael Lorenzen or Clayton Kershaw. The hitting pitcher wins this round, and the Silver Slugger.

5. Here's catcher Erik Kratz facing reliever Dylan Floro, in what is probably the most normal-looking version of this type of matchup:

Kratz -- who has made five pitching appearances as a big leaguer -- throws fastballs that are neither too hard nor too soft: high 70s, low 80s, around the strike zone. Floro takes a good swing and makes solid contact, sending a 97 mph ground ball to short. Ground balls hit that hard scoot through the infield about 29 percent of the time. Floro runs well to first, and gets there in a respectable 4.25 seconds from the left side. Nobody would fool a scout, but everybody looks like athletes and the result looks like baseball. The hitting pitcher wins the matchup, but this is one for the cancel-each-other-out hypothesis.

That covers five of the 12 last year. The other seven:

Bryan Holaday threw two mid-70s fastballs, both strikes, to Drew Anderson, who hit a hard grounder (96 mph; .270 expected BABIP) to the third baseman. Anderson loped to first and was thrown out easily.

Hernan Perez threw a first-pitch eephus in the dirt to Alex Wood, then ramped up his velocity: 68, then 77, 75 and 79, striking Wood out swinging. Wood slumped badly as he Charlie Brown'd back to the dugout.

Kratz again, this time against Caleb Ferguson, threw an 80 mph strike, then an 82 mph strike, which Ferguson struck well on the ground. Kratz fielded the comebacker (96 mph) and turned a double play.

Victor Caratini threw a series of mid-60s pitches to Matt Bowman, who hit the second one he saw back up the middle (92 mph, .340 xBABIP). Caratini was standing there unprepared, his glove closed against his chest, but managed to kick the ball as it passed him, and his shortstop threw out the very slow Bowman.

Alex Avila threw a 76 mph fastball to Yency Almonte, who tapped it weakly (68 mph, xBABIP .130) to third base. He was out.

Jedd Gyorko got Tyler Cloyd to ground out to shortstop (95 mph, .530 xBABIP) on a 3-1 pitch. All five pitches were between 74 and 77; the shortstop had to make a diving play to get Cloyd, who was barely running.

Cory Spangenberg faced Luke Jackson, who spent part of the at-bat laughing in the batter's box. Spangenberg threw 83-85, fielding Jackson's comebacker (88.4 mph exit velo, .080 xBABIP) and turned one of the strangest-looking double plays I've ever seen:

John Ryan Murphy, meanwhile, lobbed pitches in the low-60s to Brock Stewart earlier this season. Stewart popped out foul and looked thoroughly uninterested in the whole thing. Later in the game, he doubled off Murphy.

One of Bill James' inventions is Log5, a method of figuring out how often one team should beat another team if you know each team's winning percentage. It can also be used to estimate how well a hitter would do against a pitcher, if you know each player's stats.

We plugged hitters' pitching stats and pitchers' hitting stats into the Log5 equation* to estimate who should win. The answer is that the hitters pitching should: Given their established levels of performance, pitchers should hit only about .180/.210/.270 against position players pitching.

That feels too low, to be honest, given what I just watched. But the ridiculously small sample doesn't altogether lie: Since 2000, 35 hitting pitchers have hit .188/.257/.313 against pitching hitters. It's hard to know what to make of it, and not just because of the sample size. It's hard because a lot of these plate appearances don't really look like one another at all. In some cases the hitting pitcher isn't trying at all. In some, the pitching hitter isn't trying at all. This moment of peak baseball weirdness is all the weirder because, unlike regular baseball, we can't tell who isn't trying and who is just terrible.

But the aggregate result is a lot more like baseball than I expected. About 65 percent of the pitches thrown were for strikes, compared to 64 percent for the league as a whole; the average exit velocity of the 13 balls tracked by Statcast era was 88 mph, which is exactly the league-average exit velocity this year. There are fewer strikeouts and fewer walks than normal but, you know, it's baseball. It somehow avoids getting too weird, even when it is.

Stewart, the Dodgers pitcher, was finally relieved -- and replaced by the Dodgers' catcher, Russell Martin. He got the last out of the game on a fly ball hit by Murphy.

*We used the Log5 method to first estimate walk rates, then strikeout rates on non-walks, then home run and hit rates on balls put in play, and used that to create an estimated slash line.