The Mets placed outfielders Brandon Nimmo and Mark Canha on the injured list after a New York coach tested positive for cancer.
The team did not have a player for the home opener.
Mets manager Buck Showalter confirmed that a member of his staff tested positive for the coronaviruses and was absent Friday.
The team didn't say if Nimmo and Canha tested positive. The rules for returning to the roster under baseball's new labor agreement are different for players who are vaccine free versus those who aren't, but Showalter wouldn't say whether either player is.
Showalter said he tested negative.
Second baseman Jeff McNeil was moved to left field in Canha's place, while center fielder Nimmo was moved to right field. Robinson Can played second base.
Canha missed out on his first home opener with the Mets after signing a $26.5 million two-year contract as a free agent in November. He had a.381 batting average with four walks on the New York road trip.
Nimmo could become a free agent next year if he missed the home opener. The leadoff hitter was 8-for-24 with six runs and four walks on the road trip.
Showalter said that it is part of life in the 2020s.
To replace them on the active roster, the Mets recalled outfielder Nick Plummer from Triple-A Syracuse and selected infielder Matt Reynolds from Syracuse.
Showalter said that they had a couple other people standing by in case they needed it.