"It doesn't have anything to do with the fracture," Alderson said.
D'Arnaud, who was hitting .317 in 41 at bats before his injury, has been on the disabled list since being hit in the hand by a fastball from Marlins reliever A.J. Ramos on April 17. His Minor League rehab assignment began Wednesday, when he caught five innings and went 0-for-3 at the plate. On Thursday he went 0-for-3 as the designated hitter, removing himself after feeling discomfort in his wrist during his third at-bat.
The Mets had previously hoped d'Arnaud would rejoin the team next week in San Diego.
Kevin Plawecki has hit .218 in 26 games in d'Arnaud's place, while playing to mixed defensive reviews. Manager Terry Collins has indicated Plawecki likely would be sent down for more seasoning when d'Arnaud returns.
• Alderson said there is no update on the condition of third baseman David Wright, who continues to rehab at spine guru Dr. Robert Watkins' facility in Los Angeles. Collins expects Wright to make a locker room appearance next week with the team in nearby San Diego. But the timetable for his return from spinal stenosis is still unclear. Wright hasn't played since April 14.
• Collins said reliever Bobby Parnell reached 95 mph while on rehab assignment at Double-A Binghamton. Parnell, who underwent Tommy John surgery in 2014, has experienced multiple setbacks and struggled to find his pre-surgery velocity. Collins said both Parnell and reliever Vic Black, who is rehabbing a neck injury, are close to returning.
Joe Trezza is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.