BOSTON -- Lefty Martín Pérez, signed as the fifth starter in December only to vault all the way up to the second slot due to a variety of unforeseen circumstances, unfortunately looked more like the former in his debut on Saturday.

Clearly laboring in his first two innings, Pérez dug his new team into a five-run hole, and it never recovered in a 7-2 loss to the Orioles.

The Red Sox looked so impressive in every way in Friday’s season opener -- a 13-2 bashing of the Orioles.

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But the old saying that momentum only goes as far as your next day’s starter was very evident by the early innings on Saturday.

Though Pérez recovered nicely, keeping the Orioles off the board over his final three innings, it wasn’t enough.

Fair or not, the Red Sox are going to need better results from Pérez considering Chris Sale is out for the season, David Price was traded and Eduardo Rodriguez’s status is uncertain as he recovers from COVID-19.

In this shortened season, when everything is going to be magnified, Pérez expressed confidence that he will rebound quickly from this opening misstep. His next start will be in New York against the Mets on Thursday.

“I feel great, and we still have 58 more games,” Pérez said. “I have the conviction that I can do the job good and that happens, it’s part of the game. I’ll be ready for my next start.”

It would be one thing if Pérez came out of the start throwing his hands up and wondering where it went wrong, but he had a strong idea of what happened and said he will do something about it next time. The issue was his failure to pound his cutter inside those first two innings.

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“When I got to the dugout after the second, I just told myself I needed to be more aggressive, and that’s what happened,” Pérez said. “More aggressive, throw more strikes and throw the pitches where I wanted, use more of the cutter in. And I think my cutter was there [after the second inning], and it was hard for the hitters to hit that pitch inside.”

On some days, Pérez would have been rewarded for settling down from that rocky start. For a loaded Boston offense, a five-run deficit on a warm summer day at Fenway Park won’t always be a big issue.

But on this day, they were shut down by righty Alex Cobb, who looked like the Cobb of a few years ago with the Rays in his first start in 15 months. Cobb held the Sox to four hits and one run (a solo shot by Mitch Moreland, the final batter he faced) over 5 1/3 innings. He walked none and struck out six.

Pérez, meanwhile, gave up six hits and five runs (four earned) in his five innings, walking two and striking out two.

“Really good [after the first two innings], especially the last two,” said manager Ron Roenicke. “If we can get him to pitch like that from the get-go, he’ll be back where he needs to be.” 

The question marks on the pitching staff rest not just with the rotation.

Aside from Brandon Workman and Matt Barnes, there are a lot of roles to be determined. After the offense chipped a 5-0 deficit to 5-2, Roenicke went to the recently acquired Dylan Covey to start the seventh. That didn’t go well, as Covey gave the two runs right back.

“We thought that was a great spot,” Roenicke said. “We talked about in the game where we could get to him and how we could basically break him in and get him a couple of innings. If it was a tight ballgame, we didn't think that was fair to him. We thought that was a really good spot to put him in.”

After the game, Covey was optioned to Triple-A Pawtucket. The Red Sox will make a corresponding roster move on Sunday.

“We liked what we saw today and had talked about this move before the game and actually the last couple days, but I thought he looked good,” Roenicke said. “His offspeed pitches were good. He threw strikes but he’s not built up, and we need to get him there. Try to extend him to three innings the next time and then maybe four after that, and then we’ll see what our need is when he gets stretched out when he’s strong, and so that’s that move.”

Much of Boston’s pitching staff could be a revolving door over these next couple of months.  

In this 60-game season, the Red Sox just hope they can get enough pitching to supplement what should be a lethal offense, albeit one that had an off day on Saturday.