The Mets don’t know when — or if — Kodai Senga is coming back to the rotation. 

And Jose Quintana has been far from his best of late. 

But they’ve gotten a complete-game shutout from Luis Severino over the weekend and a strong outing by Sean Manaea, which gave them a boost against the Marlins. 

Then David Peterson went out Monday night against the Orioles and delivered what manager Carlos Mendoza called “probably the best outing of the year.” 

The lefty gave up just an unearned run until a wacky seventh inning of the Mets 4-3 win over Baltimore at Citi Field. 

He tossed a season-high seven innings, and were it not for a fluky balk that scored a run and briefly threw Peterson off his game, his line would have been even better. 

Still, over Peterson’s last four starts, he’s allowed just five earned runs in 24 ¹/₃ innings (1.85 ERA). 

Perhaps the best sign of all Monday from Peterson was the fact he issued only one walk after handing out seven of them over 11 ¹/₃ innings in his previous two starts. 

The key, Peterson said: “Just be in the [strike] zone, attack and trust myself, trust the defense, trust [Francisco Alvarez]. … I felt very consistent with all my pitches and could throw anything at any time.” 

Peterson had given up just a pair of baserunners until two outs in the fifth, when Ramon Urias doubled to left.

A throwing error on a pickoff attempt by Peterson moved Urias to third and he scored Baltimore’s first run on a Jackson Holliday groundout. 

But Peterson and the Mets held a 3-1 lead in the seventh when his night got thrown off, as Ryan Mountcastle led off with another double and moved to third on a groundout. 

After Peterson responded by striking out Colton Cowser for the second out, he lost track of the pitch count with Urias at the plate again and was called for a balk that sent Mountcastle home to make it 3-2. 

An obviously frustrated Peterson — and Alvarez behind the plate — then watched as Urias sent Peterson’s next pitch out to left-center. 

The solo shot tied the game before Alvarez won it in the bottom of the ninth with his own home run. 

The emotional win was important after the Mets opened their crucial homestand by dropping a series to Oakland and failing to complete a sweep of last-place Miami as they try to stay in the National League wild-card race. 

The strong start against an Orioles team that is fighting for the top spot in the AL East was promising, but Peterson said the focus remains on the day-to-day. 

“I understand the perspective of ‘Are we in, are we out?’ ” Peterson said. “We’re focused on the game today.” 

That was good enough on Monday.