What’s the deal with Eduardo Rodriguez?

We're in that sweet spot now, where the early-season sample dust is starting to settle and we can make some clear judgments about players and teams. The Blue Jays: probably not that good. Chris Sale and Dallas Keuchel: probably aces (again). Bryce Harper: probably getting a lot of money in two years.

Some mysteries remain, though. Take Eduardo Rodriguez. The Red Sox southpaw has pitched 23 ¹⁄₃ innings this year, with a 2.70 ERA. That’s miles ahead of where he was in his 2015 debut (3.89 ERA) or his 2016 follow-up (4.71 ERA). Is this another early-season fluke, or the beginning of a legitimate breakout? Let’s dive into the numbers and try to find some answers.

Point: His advanced stats aren’t that good.

Beyond his ERA, Rodriguez hasn’t really impressed in 2017. His 4.42 FIP, when adjusted for park and league factors, checks in at 8 percent worse than average. He gets a little bit better when you look at xFIP — a 16.0 percent home run/fly ball rate hurts his cause a bit — but his 3.96 xFIP is only 4 percent better than average. Overall, he looks like the same pitcher he’s always been.

Rodriguez’s peripherals shed some light on the situation. While he’s struck out 32.6 percent of opposing hitters, he’s also walked 14.7 percent of them; the resulting K/BB (2.21) is actually worse than his career mark (2.52). Plus, his ground ball rate has shrunk to 26.0 percent, leaving him much more vulnerable to round-trippers. Overall, it seems like the changes he’s made haven’t benefited him, despite what his ERA would suggest.

Counterpoint: His advanced advanced stats are off the charts.

Look even deeper — yes, it is that deep — and you’ll see a different story. By DRA, Baseball Prospectus’s measure of how many runs a pitcher should have allowed, Rodriguez has been one of the best pitchers in baseball. Only Sale and Keuchel have topped Rodriguez’s 1.01 DRA. By cFIP, he remains elite, placing fifth in the majors behind Sale, Noah Syndergaard, James Paxton, and Michael Pineda.

Why the discrepancy? E-Rod’s pitched two of his games in Fenway Park, with road outings in Comerica Park, Rogers Centre, and Camden Yards — four of the more hitter-friendly stadiums in the game. As the result, his pitcher park factor is 116, the sixth-highest among hurlers with 20 or more innings. (You’ll notice four of the pitchers ahead of him also play for the Red Sox.) This custom park factor is considerably higher than the 105 FanGraphs gives to him, which doesn’t take into account the specific stadiums in which he’s pitched.

There’s also the matter of his batted-ball profile. Fly balls can be a curse, when they bring home runs; if they stay in the yard, though, they’ll be a blessing for the pitcher who induced them. DRA and cFIP give some credit to Rodriguez for his .239 BABIP, since a clean 74 percent of the balls in play against him have been in the air. Maybe the new Rodriguez really is better than the old one.

Point: He’s not throwing strikes at all.

Over his first five games, E-Rod has put just 40.2 percent of his pitches in the strike zone — by far the lowest clip of his career:

Image via FanGraphs

He hasn’t gotten hitters to chase, either — his 28.3 percent O-Swing rate is below the major-league average of 29.9 percent. This means he’s throwing fewer strikes, which has two effects: It inflates his walk rate, as we’ve seen already; and it puts him in more hitter’s counts, forcing him to throw more hittable pitches. Having more balls in the count is pretty much always a bad thing.

Counterpoint: Maybe that’s not a bad thing.

Of course, “pretty much always” isn’t always, for a few reasons. First off, Rodriguez has picked up slightly more strikes than you’d expect. For all four of Rodriguez’s starts this year, Christian Vazquez has been behind the plate. (Vazquez has started only 12 of Boston’s 28 games overall, so he’s not the primary catcher.) His elite framing has helped Rodriguez put up a 59.2 percent strike rate, far above the 57.1 percent strikes we’d expect from his zone and O-Swing rates.

Second off, with the shift outside the strike zone has come an uptick in swinging strikes. Rodriguez has gotten a whiff on 14.9 percent of his pitches — by far the highest clip of his career:

Data via FanGraphs

Third off, Rodriguez hasn’t struggled with command this year. His CSAA — Baseball Prospectus’s measure of how well a pitcher hits his spots — is 0.92 percent, marking the first time in his career he’s been positive. In this regard, he ranks 41st out of 141 pitchers with at least 20 innings. Rather than the yips, this seems like an intentional move on Rodriguez’s part.

Point: His arsenal hasn’t changed that much.

Rodriguez is throwing the same pitches he’s always thrown, and at the same levels (for the most part):

Image via Brooks Baseball

The slight increase in changeups — from 17.9 percent in 2015-16 to 22.7 percent in 2017 — is probably because of Rodriguez’s opponents. This season, 17.9 percent of the hitters he’s faced have been fellow lefties, down from 22.8 percent in the prior two years*. As he starts to go up against more southpaws, he’ll rely on the slider and cutter a little more, and the changeup a little less.

*No, those aren’t typos; the numbers really are that similar. I’m just pissed none of them included 69.

Nor has Rodriguez’s velocity gone up this year. In fact, he’s thrown everything softer than ever before:

Image via Brooks Baseball

The definition of insanity (Editor’s note: It isn’t the real definition. You’re on thin ice here, Romano.) is doing the same thing over and over again and expecting different results. Rodriguez is using the same pitches he always has, and at inferior velocities, too. So why should we think he’ll continue to dominate like this?

Counterpoint: His location has changed a lot — especially on his out pitch.

Here’s the location of Rodriguez’s changeups for each year in the Show:

Images via Brooks Baseball

He’s always gone for the same spot with the cambio — down-and-away to righties, as you’d expect. This year, though, he’s done so more often. A full 69.1 percent of his changeups** have gone to those five down-and-away squares in the Brooks strike zone, up from 57.5 percent in 2016 and 56.1 percent in 2015.

**Ah, there it is.

In terms of average location, Rodriguez has moved the pitch down by a lot, and the results have spoken for themselves:

Image via Brooks Baseball

Together with his four-seam fastball — which he moved up in the zone starting last year, and which also got more whiffs thanks to its location shift — this gives him a couple of pitches to attack hitters with. If they lay off the changeup, it’ll go for a ball, and if they hack at the fastball, it’ll go in the air; the whiffs he gets otherwise, to this point, have made up for that.

23 ¹⁄₃ innings is still a pretty small sample — we don’t really know who E-Rod is, and we won’t until it’s June or July at the earliest. Based on what we’ve seen thus far, though, we can surmise that he’s taken a step forward. While his repertoire has stayed the same, he’s tweaked his location to get more whiffs and run a lower BABIP. Whether that approach continues to work for him, we’ll have to find out.

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Ryan Romano is the co-managing editor for Beyond the Box Score. He also writes about the Orioles for Camden Depot, sometimes. Follow him on Twitter if you enjoy angry tweets about Maryland sports.