Which ERA is the biggest mirage in early 2021?

The Oakland A’s are back on track after a slow start. They lost six straight, but now have won four of their last five, climbing back toward .500 in less than a week.

One big reason for the recent success is that the lineup began scoring. They were making great contact the whole time, but for a week it all found gloves or foul territory, and now it’s hitting turf or bleacher seats like it’s statistically inclined to do. This was mostly a correction of a small-sample fluke.

The pitching is another story. They got hammered during the early slump, but it wasn’t unlucky. They simply gave up lots of hard hits and issued way too many walks. There’s still a small-sample fluke involved, but it’s that they rolled out of spring training and immediately faced two of the best lineups of this decade, nonstop for 10 days. That’ll make you look worse than you really are.

Rotation, first 5 gms: 22 ip, 24 runs, 21 Ks, 10 BB, 5 HR, .402 xwOBA

Yikes. Overall the staff allowed 45 runs in those first five games, with everyone from the setup crew to the mopup men furthering the damage out of the bullpen.

They’ve begun to settle down since then, with just 24 runs over their next six contests, four of which were victorious. They’ve gotten a couple quality starts, and nobody has blown a lead out of the bullpen yet, nor allowed a large advantage to whittle down enough to require a save situation.

But the season stats are still ugly. Out of 13 pitchers on the current active roster, only two of them have good ERA marks, with one more barely qualifying as better than average in a two-inning sample. The full list, through 11 games entering Tuesday:

Starters

• Chris Bassitt, 4.96 ERA
• Sean Manaea, 5.06
• Jesús Luzardo, 6.10
• Cole Irvin, 7.45
• Frankie Montas, 8.31

Relievers

• Lou Trivino, 1.17
• Yusmeiro Petit, 2.84
• Deolis Guerra, 4.50
• Jake Diekman, 5.06
• J.B. Wendelken, 5.79
• Jordan Weems, 9.00
• Sergio Romo, 9.82
• Adam Kolarek, 16.88

Holy run prevention, Batman. That list is haunting.

Again, the point here isn’t that these ERAs aren’t earned. They really did get knocked around in these games. The point is that some, or most, or all of these pitchers are better than this, and a couple bad innings will come out in the wash over six months. At least one of them probably will continue to struggle and never recover this year, because that happens with pitchers all the time, but we don’t yet know which one nor how many of them will do so. And all of them have enough track record to earn more leash toward finding out.

Kolarek has faced 17 batters. He allowed homers to the first two, so his numbers accurately reflect that. But unless he’s suddenly going to allow a dinger per inning, instead of being the weak-grounder factory that he’s been the last three years, his stats will normalize eventually. Guerra has thrown two innings, in one game. Weems has worked one inning. Nobody in the pen has completed eight frames.

In the rotation, everybody got better in their second turn, either by working deeper into the game and/or allowing fewer runs. Bassitt lowered his run output even further in his third start.

The question is not if some of these bad ERAs are early-season mirages. It’s how many of them are, how much will they improve, and how quickly it will happen.

Statcast can provide some objective answers. Looking at the difference between expectation (xwOBA) and reality (wOBA), the unluckiest arms so far have been Kolarek and Romo. They still haven’t been good, but they haven’t been quite the unmitigated disasters that their ERAs suggest. Next is Luzardo, who is missing bats like crazy even when he’s run into some barrels along the way.

As for fielding-independent performance, the biggest gaps between FIP and ERA belong to Diekman, Wendelken, Montas, and Kolarek, each by more than two runs, followed by Luzardo. They’ve had the worst BABIP luck compared with their rates of strikeouts, walks, and homers.

But those measures only tell us who has been sold short compared with the actual contact they’ve allowed. We’re also talking about who will simply stop allowing so much hard contact in the future.

Here’s my gut instinct off the top of my head. Luzardo will finish with the best ERA in the rotation, but Montas will see the biggest and fastest drop from present because his is so high right now. Bassitt and Manaea will also improve of course, and Manaea will be the first to drop under 4.00 because he faces the Tigers next. I’m withholding judgment on Irvin entirely until we see him face anybody but the Astros.

In the pen, Kolarek is an easy pick because I think he’ll turn out fine. Whether that means a 2.00, 3.00, or 4.00, it’ll be a darn sight less than double-digits. However, it might take a minute, because he works in short stints so it’ll require time to build up enough innings to offset, and any stray run along the way due to unlucky BABIP will be a setback. Diekman is another easy choice since his 2020 breakout looked real, and I’ll go with Weems as a more interesting guess since I’m still a big believer despite a rocky spring.

Or, something completely different could happen. All I know is that more than two of these pitchers will finish 2021 with ERAs under 4.50, and that’s grossly understating it.

Who are your picks to click, this week and beyond? Let’s discuss in the comments!