The first pitch has yet to be thrown and the 2021 MLB season is already beset by COVID-related issues.

Thursday’s Opening Day game in D.C. between the Washington Nationals and New York Mets has been postponed “out of abundance of caution,” commissioner Rob Manfred confirmed to ESPN, after Nationals manager Mike Rizzo acknowledged Wednesday that his team could be short five players and a staffer after one team member tested positive for coronavirus.

While Manfred initially told ESPN that the Nats-Mets opener would instead be played on Friday—initially scheduled as a day off—ESPN’s Buster Olney reported on Thursday that the Friday game has also been postponed.

MLB is currently not requiring vaccinations but is instead “strongly encouraging” players and staff to get shots by issuing a memo relaxing COVID-19 protocols for teams where 85 percent or more of key personnel are fully vaccinated.