The Philadelphia Phillies placed second baseman Scott Kingery, right-handers Tommy Hunter and Hector Neris and left-hander Ranger Suarez on the COVID-19 list, the Philadelphia Inquirer reported Thursday night.
The Phillies had revealed the four players were placed on the 10-day injured list without specifying a reason.
Major League Baseball recently instructed teams not to disclose if a player is played on the COVID-19 list.
According to the Inquirer, seven Philadelphia players tested positive for the coronavirus in June.
First-year Phillies manager Joe Girardi was quizzed on Thursday about the situation and said he couldn't discuss it because of medical privacy reasons.
"What I can tell you is they're on the injured list, and that's about all I can tell you," Girardi said. "MLB has given protocols on how to handle it. I don't have a timetable on those players. I can't really answer that question. As soon as I get an answer, I will give it to you."
Philadelphia general manager Matt Klentak told the Inquirer on Monday that the club would place "a handful at minimum" of players on the COVID-19 list.
Thursday's revelations come one day before the Phillies begin their team workouts for the upcoming season.
Kingery, 26, batted .258 with 19 homers and 55 RBIs in 126 games in 2019 in his second major league season.
Hunter, 34, is entering his third season with the Phillies and 13th overall in the majors. He pitched in just five games last season because of a forearm injury.
Neris, 31, is entering his seventh campaign, all with Philadelphia. He recorded a career-best 28 saves last season while going 3-6 with a 2.93 ERA in 68 appearances.
Suarez, 24, went 6-1 with a 3.14 ERA in 37 relief appearances with the Phillies last year. He also made four appearances (three starts) for Philadelphia in 2018, going 1-1 with a 5.40 ERA.
--Field Level Media