SAN FRANCISCO — Justin Verlander was “all good” on Sunday in taking his next step toward his Mets debut.

That assessment came from manager Buck Showalter after the team’s co-ace threw 43 pitches over three innings in a live batting-practice session in Port St. Lucie, Fla.

“He went out there and got after a couple of pitches toward the end — he felt good,” Showalter said before the Mets faced the Giants at Oracle Park.

Verlander’s next step will be to pitch in a minor league rehab game on Friday.

The location of that start has not been finalized, according to Showalter, but it’s possible he will remain in Florida and pitch for Single-A St. Lucie.

After that Verlander would potentially be in position to start in Detroit — where he spent the first 12 seasons of his major league career — on the Mets’ next road trip.

Verlander has been on the injured list since the season started with a strained teres major muscle near his right armpit.

“I have texted him back and forth multiple times and he is doing good, feeling good,” Showalter said. “He is feeling good and anxious to get back.”

Showalter said he’s confident one rehab start in the minors will be enough for Verlander given all the work he’s put in to reach this point.

But the manager cautioned Verlander’s first start back could be shortened.

The manager said this timeline is what the Mets projected after Verlander was placed on the IL.

“Probably give or take a few days,” Showalter said. “If everything goes well he and Max [Scherzer] would probably be a couple of days apart.”

Scherzer is scheduled to return next Monday from his 10-game suspension for violating MLB’s rules on foreign substances.

The Mets still have not announced a starting pitcher in Scherzer’s spot for Tuesday’s series opener against the Nationals.

Showalter’s preference would be to avoid going with a bullpen game and Jose Butto’s recall from Triple-A Syracuse would be contingent upon the Mets placing a player on the IL.

Butto was optioned to Syracuse last Monday, meaning he can’t return within 15 days unless the corresponding roster move is for a player placed on the IL.

Sunday’s game was the Mets’ 17th on the road this season — tops in the major leagues.

The Brewers and Phillies are next with 13 road games apiece.