D'Arnaud has been sidelined since fracturing his right pinkie when he was struck by a pitch from Miami Marlins reliever A.J. Ramos on April 19. He more recently was slowed by a bone bruise in his right wrist.
D'Arnaud completed a rehab assignment with Triple-A Las Vegas on Tuesday.
The Mets are accelerating d'Arnaud's return because rookie catcher Kevin Plawecki was scratched from Tuesday's series opener against the Giants with dizziness. Plawecki also missed two weekend games at Arizona with that symptom, which has been blamed on a virus.
Plawecki dealt with vertigo last season in the minors but said this past weekend that the current issue is unrelated.
Plawecki, who initially was ticketed to be demoted when d'Arnaud was activated, instead might land on the DL.
Second baseman Dilson Herrera also is nearing a return from a rehab assignment, but a team official said Herrera's return will not be simultaneous with d'Arnaud rejoining the Mets. Herrera landed on the DL on May 15 with a fractured tip of his right middle finger, which he suffered during a pregame fielding drill.
In addition, the Mets announced Bobby Parnell is due to rejoin the club Wednesday and be activated from the disabled list within a few days.
The Mets will return Parnell, the team's former closer, to the majors for the first time since he pitched on Opening Day in 2014, then underwent Tommy John surgery eight days later.
He appeared in his final rehab game Tuesday with Double-A Binghamton. He tossed a scoreless inning against Bowie, albeit with a walk, a hit batter and a wild pitch.