What I didn’t see back then was that his change-up had gotten far better, and yeah, it does help when you’re not tipping your pitches every other inning. It also helps when you use two other good pitches to set up your best one. After a forgettable first start in Detroit, Rodriguez has been gunning for the strikeout and hasn’t looked back since.

Let’s start with the second half of 2016. Rodriguez had been back, but he was inconsistent. As the calendar turned to August, he started ramping up the strikeouts, culminating in a 5.1-inning effort in Tampa where he struck out 13 batters. 13 out of a possible 16 outs. That’s insanity, and not something you would’ve expected out of E-Rod. The key for him was how effective his changeup was with two strikes during the last two months of the season. Whenever Rodriguez threw his changeup in a two-strike count, batters whiffed 31 percent of the time. His changeup was the pitch batters swung the most at, and it was filthy enough to get a swing and a miss nearly half the time they swung. If the ball ended up being put in play, it was a grounder over 70 percent of the time. Rodriguez had found a strikeout pitch in his superb changeup, and with a good fastball/slider combination supplementing it, it looked unhittable.

Come 2017, and Rodriguez has fully embraced the fastball/changeup life. His sinker and slider are still there, but he’s not throwing them as much anymore. And why should he, when everyone he faces still can’t hit his changeup? Apart from his lackluster Detroit start, Rodriguez has been getting a lot of whiffs with the changeup, even in his weird one-inning stint in Toronto.

The Pittsburgh game is a strange one, as he got 14 whiffs and eight strikeouts, but also walked four and served up a dinger to Andrew McCutchen. Everything after that? Stellar. Rodriguez got five whiffs in a single inning of relief in Toronto, and then went on to stifle two very good offenses in Baltimore and Chicago. In Baltimore, you can see that most of the strikeouts early were with the fastball, and then he slowed down and used the change-up as the game went on.

As long as you don’t look at ERA predictors, Rodriguez was dicing up the Orioles in that one. They had one hit over six innings, but Rodriguez also walked five while striking out seven. Changeups and sliders don’t usually end up in the strike zone anyway.

The Cubs game was something else. I don’t know about you, but I think Eduardo’s figured it out:

Assuming Rodriguez’s night is done, yes, he finished with 16 swing-and-miss, nine on the changeup. One run on five hits, two walks, nine Ks https://t.co/ehmqJI4nTz

— Jen McCaffrey (@jcmccaffrey) May 1, 2017

Remember how prolific Rodriguez was with his changeup in two-strike counts last year? Because he got better with it. That’s not hyperbole. Batters have swung at the changeup 64 percent of the time in those counts, and they’ve hit nothing but air two-thirds of the time. That’s a wipeout pitch. And it isn’t particularly better for batters in general either. Overall, batters have swung at his changeup 47 percent and whiffed over half the time. There’s only so many times I can call that pitch filthy or disgusting until it starts sounding like a Gordon Ramsay soundboard. But if you’re still not convinced – and if you’re not, I respect the stubbornness – here’s what he did to a strong Cubs lineup:

I counted five strike-three whiffs on his changeup alone, possibly six if you count the first as a missed location. He’s getting what he wants out of that pitch.

Of course, unless you’re Mariano Rivera or a knuckleballer, you’re not going to survive on just one pitch. Rodriguez’s fastball is no slouch either, as it still gets swings and misses over 11 percent of the time. He doesn’t use his slider or sinker much, but the slider still gets the occasional whiff, and the sinker generates grounders, which he’ll need if he wants his 26 percent groundball rate to improve. Overall, his swinging strike percentage (14.9%) is better than those posted by Noah Syndergaard, Sean Manaea, and James Paxton – three pitchers who are (or in Thor’s case, were) racking up the strikeouts. This isn’t a fluke.

I don’t know if you can say Rodriguez has “arrived”, since he was good for a sizable part of the 2016 season. He’s been here for a while already. But what you can say is that he’s gotten better. From what we saw from him last year and what we’ve seen so far, that’s an exciting statement to make.

Photo by Bob DeChiara – USA TODAY Sports

I bet you are. It’s hard not to get excited about a flame-throwing left-handed starting pitcher who was crazy successful in his major league debut. Make no mistake, there’s a lot to like about the new hot thing in Boston.

Rodriguez has all the hallmarks of a successful starter long-term: velocity, command, and multiple plus-pitches. He also carries a nice little prospect pedigree, though he’s been outshined at times by other players in both Baltimore (Dylan Bundy, Kevin Gausman) and Boston (Blake Swihart, Mookie Betts, maybe Henry Owens).

When the Sox dealt Andrew Miller for Rodriguez last season, it was seen to be a clear win for Boston at the time — but Rodriguez has continued to improve and develop since landing in the Red Sox system. That velocity I spoke of … it has ticked upwards since Rodriguez arrived in Pawtucket, and he’s made some adjustments to his changeup. The result is a three-pitch starter, where all three pitches project as plus over the long-term.

Eduardo Rodriguez’s debut, a stellar outing of just three hits and two walks over seven and two-thirds innings, set the expectations high for a strong start to his career. While PECOTA’s projections don’t have Rodriguez accumulating massive value this season, it’s primarily due to the fact that our favorite prognosticator didn’t anticipate real big-league innings. Now that the 22-year-old lefty has busted through the door, it’s time to see how things might play out over the course of two-thirds of a season in the Boston rotation.

To estimate how Rodriguez might perform in his rookie year, I tried a different method than just accessing the projection systems like PECOTA and their ilk. Instead, I wanted to see how other rookie starters have fared over the past five years, in this new and exciting world of a strikeout per inning and pitching dominance. Specifically, I was interested in lefty starters.

Rodriguez has all the hallmarks of a successful starter long-term: velocity, command, and multiple plus-pitches.

As you might expect, there are far fewer lefty starters than righties who’ve made their debuts from 2010-2014. From my initial pool of 185 pitcher seasons, I cut that down to just 49 left-handed starting pitcher seasons … and that number double-counts borderline “rookie” seasons by Mike Minor, Wade Miley, and Scott Diamond.

From there, I tried to identify a few pitchers most like Rodriguez: high-velocity guys with a similar pitch mix and/or prospect background. As you might imagine, several rookie seasons fall out of contention very quickly — there simply isn’t much to learn about Rodriguez from Hisanori Takahashi’s 2010 debut with the Mets at the age of 35. And since I just looked at the rookie seasons, remember that the initial first-year stat lines don’t necessarily reflect the whole future. Guys like Danny Duffy of the Royals and Dallas Keuchel had ignominious debuts, but eventually settled into productive roles. For Keuchel, “productive” means thrusting himself into the discussion for the Cy Young Award. Truly, anything is possible.

Anyways, before we get into specific comps, let me give you a little info about the total population of lefty rookies from 2010 to 2014. The first takeaway I got from this list is this: the odds are pretty good that Rodriguez could be pretty good — if he makes it to 40 or more IP. My list of 49 seasons includes 21 seasons that the pitcher snagged an ERA of 3.99 or better — meaning nearly half of qualified rookie starters had what I’d consider “good” run prevention in their debut season. FIP was even better … 23 starters posted a FIP below 4.00.

The pitchers who had the worst peripherals tended to be the guys without a strong prospect pedigree. The aforementioned Keuchel had the worst FIP of any lefty starter in a debut season (5.74), but most of the other guys near the bottom of the list were top prospects who had seen stock decline earlier in their minor league career (guys like Drew Pomeranz and Christian Friedrich) or guys who were not much of a prospect to begin with (Brad Hand, Pedro Hernandez, Vidal Nuno). A couple of guys I’d consider to be similar in pedigree to E-Rod: Danny Duffy had a rough start (4.82 FIP and 5.64 ERA), as did Tyler Skaggs (4.86 FIP and 5.12 ERA).

So here are three guys that I think pose interesting comps to Rodriguez, in order from worst to best comparable expectation, based on gas, age, and background.

#3: James Paxton, 2014

Not bad, right? The main difference I see between Paxton and Rodriguez is that Paxton leverages his velocity into a high groundball rate, actually a good bit higher than what Rodriguez brings to the table. Now, I wouldn’t be surprised to see Eduardo’s GB% start to trend up in the big leagues, given Boston’s recent focus on pitching in the zone and inducing Masterson-esque contact, but Paxton is still more of a groundball specialist than our man.

The thing that Paxton is most similar to Rodriguez in is velocity — they don’t share very similar repertoires outside of mid-90s heat on the fastball. But that’s a pretty rare weapon that they both have. Sure, Paxton has more control issues, uses a curve as a secondary pitch, and has a history of injury that E-Rod just doesn’t share. But he also averages the fastest heater in the big leagues for a lefty starter — at least he did until Rodriguez showed up. Right now, he’s got the closest thing to Rodriguez’s velocity from the left side, and he’s been able to leverage that into some pretty solid performance over in Seattle.

One could argue that Rodriguez is different enough in profile to have a very different career arc. But no one can argue that he hasn’t been pretty effective in his first 156 innings in the big leagues. Starting his career like Paxton would certainly be a win.

#2: Tony Cingrani, 2013

This may not seem quite as good as the Paxton comp, given that Cingrani has lost his job as a starting pitcher. But Cingrani was quite good in 2013, and I feel he could match up nicely with Rodriguez in terms of results. He sat around 92 mph with his fastball in 2013, but he also used it about as often as Rodriguez might … more than two-thirds of all pitches. Cingrani also featured a slider and change, and was only about a year older than E-Rod is today during his debut.

Cingrani had flaws (home run rate) that were exacerbated by his home park in Cincinnati, a power-hitter’s haven. Rodriguez has had more time in the minors to refine his stuff than Cingrani did before his debut, so I’d say the long-term outlook is brighter. For the Reds’ phenom, the breaking stuff hasn’t improved yet. But Boston’s new kid on the block already has a slider that flashes plus. For this reason alone, I think there’s less of a chance that a good introductory season is followed by a rougher transition into a bullpen role. However, Cingrani could be a “worst-case” scenario of initial success followed by trouble when secondary stuff fails to develop.

#1: Matt Moore, 2012

This is my guy. I think that we could see a very similar performance to Matt Moore’s 2012, if we pro-rate Eduardo Rodriguez’s innings for 2015. Moore started off his starting career in Tampa Bay by throwing fast fastballs, a slider, and a change. He was in his age-23 season. And like Rodriguez, most scouts and analysts believed Moore could be a mid-rotation pitcher (or much, much better than that) from the jump. Despite the prospect pedigree and the raw stuff, Moore was plagued by inconsistency during his first time through the league, and that’s something we could see with Rodriguez as well.

Even some of the peripheral numbers at the minor league level were similar between the two pitchers. Moore saw his walk rate rise and his groundball rate drop as he moved into the big leagues, but he wasn’t all that different from Rodriguez before reaching the majors.

Moore had a famously high ceiling as a prospect, and Rodriguez has never been considered close to the top prospect in the game. But practically, I could see the two as sharing similar traits, including a high strikeout rate, mild control issues, and the potential to go through an up-and-down introductory season.

Before you get too excited, remember that anything can happen. The big leagues are a place where talented pitchers go to die. But like Paxton, Cingrani, and Moore — there are plenty of rookie left-handed starters who’ve had success in their first season in the bigs recently. If a any left-handed starting pitcher is good enough to get about 40 innings, then we should expect someone of Eduardo Rodriguez’s stature and background to be a net positive in the rotation for the rest of the season, despite the inevitable growing pains.

It’s nice to have something to look forward to in the rotation for a change.

Photo by Tim Heltman/USA Today Sports Images