The Mets' Jeff McNeil runs to first base on a fielder's...

The Mets' Jeff McNeil runs to first base on a fielder's choice during the seventh inning against the Diamondbacks in an MLB game at Citi Field on May 8. Credit: Kathleen Malone-Van Dyke

BALTIMORE — All season, the Mets have trailed the rest of the majors in one category: games played.

And now they have to catch up.

On Friday when they host the Padres, the Mets begin their next big test, 33 games in 31 days to take them to the All-Star break. This isn’t make-or-break territory, but it is a proving ground, a chance to show the rest of the baseball world that they are for real, that their 30-24 record and status as the NL East leaders isn’t just an early-season fluke.

"Coming into June, we were aware of what we were nearing," manager Luis Rojas said. "We do want to stay where our feet are, we want to be present, we want to be today. But there’s no way we don’t think of the amount of games that are ahead of us."

Here are three keys to keep an eye on over the next month:

1. No place like home

The Mets will play 22 of these 33 games at Citi Field (plus another three at Yankee Stadium). That is fortunate for them, because they lead the majors with a .750 home winning percentage (15-5).

The crowds will begin to look normal, too. As of Friday, Citi Field’s capacity will increase to about 78% — 33,875 fans — with almost all of those seats being in vaccinated sections.

"I hope they absolutely make the stadium shake," Pete Alonso said of fans returning en masse. "I can’t wait for everybody to get rowdy, make some noise and make their presence felt. I miss that energy at Citi. It’s going to be great to get it back. I hope it’s a party."

2. Getting healthy

Of the Mets’ 13 players on the injured list, four should return relatively soon.

Luis Guillorme (right oblique strain) is expected back in the next day or two. Albert Almora Jr. (left shoulder contusion) is on a rehabilitation assignment with Triple-A Syracuse.

Jeff McNeil (left hamstring strain) is slated to join Syracuse this weekend. Michael Conforto (right hamstring strain) said this week that he hopes to be not too far behind McNeil.

That might be it, though. Brandon Nimmo (left hand nerve issue) and J.D. Davis (left hand sprain) are enigmas. And it seems highly unlikely Carlos Carrasco (torn right hamstring) is back before mid-July.

"The more and more guys we get back healthy, the more and more dangerous we’re going to be," Alonso said.

3. Pitching, pitching, pitching

The Mets’ rotation has a clear line of demarcation between All-Star locks/candidates Jacob deGrom (0.62 ERA), Taijuan Walker (2.07) and Marcus Stroman (2.41) in the top tier and David Peterson (6.32) and Joey Lucchesi (5.79) in the bottom tier.

It’ll get really interesting when the Mets play three doubleheaders in a week: June 19 at Washington, June 21 versus Atlanta and June 25 versus Philadelphia. They will need seven starting pitchers at the peak of that schedule crunch.

Rojas, however, said he does not see the rotation factor as a challenge. He reiterated that the Mets believe Peterson can bounce back from recent disasters and that they are comfortable going to their very effective bullpen early on days when Peterson and Lucchesi start.

"We do trust all of our guys," Rojas said.

Bonus: Is the NL East bad?

The mini-stretch within the stretch: Two weeks of games against NL East teams. It’ll be seven against Atlanta, five against Washington and four against Philadelphia.

So far, the division has been a disappointment. Only the Mets have a winning record. Atlanta has seen regression from its pitchers, especially in the bullpen. The Phillies have been mediocre in basically every way. The Nationals haven’t scored much. And the Marlins have played like last year’s playoff bid was a fluke.

That works out for the Mets, who are 4-12 against above-.500 teams — second-worst in the majors, ahead of only the Diamondbacks.

The Mets play 13 games during this run against teams that currently have winning records: seven against the Padres and Cubs this homestand, then the Yankees (July 2-4) and Brewers (July 5-7).