BOSTON -- For the last three seasons, Nathan Eovaldi has led the Red Sox’s rotation with his reliability and vast array of plus pitches. 

And that’s what made Tuesday night’s historic mishap in the 13-4 loss to the Astros at Fenway Park so stunning.

When Eovaldi hardly even broke a sweat retiring the Astros in a five-pitch first inning, it was easy to believe he was on his way to the type of performance the Red Sox have become accustomed to.

Instead, Eovaldi endured an evening of infamy, becoming just the third pitcher in MLB history to allow five homers in an inning.

“It’s frustrating,” said Eovaldi. “I don’t know how to describe it. It’s the first time I’ve had to deal with it. It’s extremely frustrating.”

The madness took place in the top of the second inning, when the Astros looked like they were taking batting practice. 

No Boston pitcher had ever allowed four homers in an inning before, let alone five. 

So what happened?

For starters, this was the continuation of the one trend that has been troubling Eovaldi this season. He has been way more homer-prone than at any other juncture of his time with the Red Sox, which started in July of 2018.

Fact 1: Eovaldi gave up 15 homers in 182 1/3 innings last season. 
Fact 2: Eovaldi has given up 14 homers in 41 2/3 innings this season.

The gopher balls didn’t hurt Eovaldi much until Tuesday. In his first seven starts of the season, he gave up three runs or fewer each time out and never more than two homers in one start.

“I just feel like the times I’ve been hit hard are the home runs,” Eovaldi said. “I feel like I’ve been able to do a good job when I get runners on base, preventing them from scoring as long as it’s not a home run.”

Eovaldi has given up a lot of hard contact on misfires in the upper portion of the strike zone this season.

But on Tuesday, it was more of a generalized location issue. And the heavy-hitting Astros are not the team to have those issues against.

It was Yordan Alvarez who got the power party started by smashing a 97.7 mph heater in the middle, outer-quadrant of the plate.

Kyle Tucker was given a gift -- a 96 mph fastball that was middle-middle, and he destroyed it.

This wasn’t just a fastball issue though. Jeremy Peña’s homer was on a 92.7 mph cutter that was also across the heart of the plate and just slightly elevated.

Michael Brantley also feasted on a 92.4 mph cutter that was belt-high and on the outer portion of the zone.

“I wasn’t locating my pitches very well, and I stayed fast with the pitch mix,” Eovaldi said. “The fastball, cutter, splitter -- they’re all low 90s, mid 90s -- and slider was not very good, and the curveball, I didn’t throw as many for strikes. I have to do a better job of mixing my pitches and attacking them differently.”

Yuli Gurriel finished the quintet of homers by unloading on a 79.8 mph curve that was at the bottom of the zone, but right across the middle. At that point, Red Sox manager Alex Cora lifted his ace after 39 pitches.

“It’s a little bit of disbelief,” Eovaldi said. “You come in with a game plan and a plan of attack -- how you’re going to come after them -- and you kind of have a backup plan in case. If neither one of them work, and they’re just attacking everything, it’s kind of a helpless feeling out there.”

Given the degree to which the Astros walloped Eovaldi, could tipping pitches have been a factor?

“Any time something like this happens, you tend to think that,” said Eovaldi. “I haven’t had a chance to look at it yet. It’s one of the things, we’ll definitely go back to look to make sure we’re not tipping or something like that.”

While the natural tendency is to dig deep for answers, perhaps it was just a wild outlier. The Astros, having faced Eovaldi in the 2018 and ’21 postseasons, know full well how tough he usually is to hit.

“[Eovaldi's] an outstanding pitcher. He probably got some balls in the heart of the plate where he didn't want to,” said Astros manager Dusty Baker. “He was throwing hard, but you know, it was our day today. There is no explanation. I mean, sometimes, you hit the great [pitchers] good and sometimes, you know, the so-so [pitchers] you don't hit them. There's not an explanation for everything. In batting practice, you can't hit that many home runs.”

Kevin Plawecki, Eovaldi’s regular catcher the past couple of seasons, had a simple explanation.

“It shows he's human, right? We all haven't seen it,” Plawecki said. “I know he's frustrated. They didn't miss anything. It seemed like just, baseball happened.”