The Oakland A’s makeshift rotation keeps getting better

The Oakland A’s makeshift starting rotation isn’t just holding its own lately. It’s outright thriving. Last week we took a closer look at Edwin Jackson and Brett Anderson, two minor league free agent signings who have been excellent since the end of July. This time, we’ll focus on the other two veteran breakouts, Trevor Cahill and Mike Fiers, who somehow one-upped them the last few days.

First, a quick update on what the rotation is doing as a whole through 16 games in August.

A’s SPs, August: 2.19 ERA, 94⅔ ip, 74 Ks, 18 BB, 7 HR, 3.19 FIP

Compare that with the rest of their season. The following table includes four stats: ERA (results), FIP (the things a pitcher can control), innings per start (durability/efficiency), and xwOBA (quality of opponent’s contact). This is just about the most complete picture you will get from such a simple table. (April includes the end of March.)

They’ve been significantly better this month in every conceivable way. Their ERA is around half what it was the rest of the year, and their FIP is a full run better than most months. Even with management frequently pulling them quickly in favor of the stacked bullpen, they’re still pitching deeper into games (likely because of fewer blowups resulting in early exits). And their xwOBA is better than league average (.327) for the first time.

On top of all this, they’re finding this success in spite of Sean Manaea. The guy who was supposed to be their ace has instead been the weak link lately, with a 5.31 ERA in four August starts (two good, two bad). He’s still having a fine season and the point of this paragraph isn’t to bash him, but rather to show that they’re doing all of this even without much help from the guy who was supposed to be their rock.

Instead, the heroes continue to be the last-minute emergency fill-ins. The afterthoughts, who weren’t on anyone’s hypothetical depth chart or trade radar during the winter. In this case, that’s the guy who got a tiny one-year deal halfway through spring training, and the August trade acquisition who cost a couple PTBNLs.

On Saturday against the Astros, Cahill was dominant. He went seven innings and faced just one batter over the minimum, allowing a hit and a walk but getting a double play to eliminate the latter. And that wasn’t against some doormat opponent, but rather the defending champs with a top-notch lineup.

On Monday against the Rangers, Fiers matched that performance almost exactly. He had one extra strikeout and also hit a batter, but otherwise their lines were identical, even down to throwing precisely 100 pitches. And while his gem came against the last-place Rangers, remember that they’re super-hot right now and have actually scored the most runs in MLB this month — even after being shut out in this game. Texas is bad because of their poor pitching, not a lack of hitting.

Cahill, Sat: 7 ip, 0 runs, 7 Ks, 1 BB, 1 hit, 100 pitches
Fiers, Mon: 7 ip, 0 runs, 8 Ks, 1 BB, 1 hit, 100 pitches

How good were those two starts by Cahill and Fiers? Here’s a list of the A’s best starts this year by way of Bill James’ Game Score, which assigns value for basic box score results like innings, runs, hits, walks, and strikeouts. (Here’s more on the simple, easy to understand formula.)

1. Sean Manaea’s no-hitter (95 Game Score)
2. Daniel Mengden’s shutout (88)
3. Mike Fiers on Monday (82)
4. Trevor Cahill on Saturday (81)

By that basic measure, these were the third and fourth best Oakland starts of the entire season, within two days of each other, against two excellent opponents, by two pitchers who were on the scrap heap last winter. They were also the second-best starts of each pitcher’s entire career — Cahill had an 82 back in 2010, and Fiers once threw a no-hitter that stands as his best. They’ve combined for 350 starts overall in the bigs.

That’s just results, though, which can vary widely due to luck or sequencing or other factors. How about the underlying Statcast data? Were the pitchers giving up loud outs, or truly inducing weak contact and missing bats and earning their zeroes? Here are the best A’s starts by wxOBA (again, average is .327).

1. Cahill on Saturday (.127)
2. Fiers on Monday (.159)

That’s it. Those were the two very best outings according to Statcast. Manaea’s no-hitter shows up in sixth place (.201). Of course, there have been other excellent performances throughout the year — the next four Game Scores after my list’s cutoff came in April or May, and the next five xwOBA’s all came before July began. But as we learned from the first table, the quality starts have come in August with much greater frequency and consistency.

Only three times this month (out of 16) have the starters failed to go five innings, and only in those same three have they allowed more than two earned runs (two of those stinkers were by Manaea, the other by Cahill on the road). Four of the A’s top 10 Game Scores, and five of their 15 best xwOBA starts, have come in August.

What does this all mean? For now, just that the misfit rotation is on an incredible hot streak at the best possible time. We can’t just assume they’ll continue to ball out like this for the rest of the year. But this was (and still is) the part of the roster that was supposed to sink any chance of contention, and instead it’s borderline carrying them while the offense has its second-worst scoring month and the bullpen aches for some rest.

Perhaps the magic will wear off at some point, but for now the A’s rotation is actually getting better as time goes on. Bet against them at your own chagrin.

Epilogue: Fun with stats

Two quick things at the end here. First, Fiers’ numbers in three starts since arriving:

Fiers, OAK: 1.47 ERA, 18⅓ ip, 21 Ks, 1 BB, 2 HR, 2.61 FIP, .311 xwOBA

That’s 21 Ks to 1 BB, which is simply unreal. He won’t keep up that pace forever, but so far he’s been everything the A’s could have hoped for and more. I was just looking for him to provide depth, but he’s pitching like a star.

Next up is Cahill’s home/road splits, in eight home games and seven road games.

Cahill, home: 0.85 ERA, 52⅔ ip, 57 Ks, 12 BB, 3 HR, 28 hits, 2.71 FIP
Cahill, road: 6.62 ERA, 34 ip, 28 Ks, 13 BB, 3 HR, 37 hits, 4.18 FIP

Those are as extreme as any splits you’ll ever see. It’s not just a matter of park effects on batted balls, either, as he’s suppressing homers everywhere and the biggest difference is in his strikeout rate. He’s been particularly stingy with hits and homers in the Coliseum, but the numbers suggest there has to be more to it than that (nearly 5 K/BB at home, only 2 K/BB on road).

“I think it’s just being at home, just comfortable,” Cahill said of his success in Oakland after Saturday’s game. “I’ve made a lot of starts here in my career, so just everything from the bullpen to warming up before the game, and going out first to set the tone. You have the ball, you’re throwing the first pitch when you’re at home, so you’re just trying to set the tone early and work from there.”

Update

I posted this article on Tuesday, less than an hour before the evening’s game started. Wouldn’t you know it, Brett Anderson went out and matched Cahill and Fiers so precisely that it’s downright eerie. The same seven shutout innings, the same one hit and one walk. Here are now three of the last four A’s starts (Cahill, Fiers, Anderson), excluding Sunday:

Sat: 7 ip, 0 runs, 7 Ks, 1 BB, 1 hit, 100 pitches
Mon: 7 ip, 0 runs, 8 Ks, 1 BB, 1 hit, 100 pitches
Tue: 7 ip, 0 runs, 6 Ks, 1 BB, 1 hit, 93 pitches

Anderson’s effort earned a Game Score of 80, tying it for fifth on the season. Three of the A’s five best starts of the entire year came in the last four days.

1. Sean Manaea’s no-hitter (95 Game Score)
2. Daniel Mengden’s shutout (88)
3. Mike Fiers on Monday (82)
4. Trevor Cahill on Saturday (81)
5. Brett Anderson on Tuesday (80) (tied with another Cahill start from May)

And once again, it wasn’t pure luck. He downright dominated, according to Statcast’s xwOBA.

1. Cahill on Saturday (.127)
2. Anderson on Tuesday (.137)
3. Fiers on Monday (.159)

For his part, this is now the third time in Anderson’s last four starts that he’s gone at least seven scoreless innings. All told, he’s allowed two runs in 26⅔ innings during that stretch (0.68 ERA), with just 12 hits and two walks and a super-low .282 xwOBA to back it all up. I’m not sure how to say this, but ... Brett Anderson is the A’s ace right now and he has a case brewing for AL Pitcher of the Month. What is happening in Oakland, Ray Fosse??