Two members of the Yankees—DJ LeMahieu and Luis Cessa—have tested positive for COVID-19.
Four members of the Twins, including third baseman Miguel Sanó, and two Red Sox pitchers are also among the MLB players who have tested positive.
The Twins announced Saturday that Sanó, catcher Willians Astudillo and minor leaguers Edwar Colina and Nick Gordon tested positive ahead of summer camp. Sanó and Astudillo are asymptomatic and under quarantine in Minnesota.
Both LeMahieu and Cessa gave the Yankees permission to release the news of their positive tests, per Inside the Pinstripes' Max Goodman, and are self-isolating at their homes.
Also in the American League, Boston manager Ron Roenicke revealed left-handers Josh Taylor and Darwinzon Hernandez contracted the virus and are in quarantine away from the team.
The announcements from both teams come after Braves skipper Brian Snitker shared first baseman Freddie Freeman, veteran reliever Will Smith, right-hander Touki Toussaint and utility infielder Pete Kozma tested positive for the virus. Snitker said Freeman has a fever and "it's going to be a while" before he reports to camp, while Smith and Toussaint are asymptomatic.
According to league health policy, the identity of players who test positive cannot be revealed by teams or MLB without their consent.
Royals catcher Salvador Pérez chose to announce his positive test on a call with reporters Saturday. The six-time All-Star said he is asymptomatic and in quarantine. Kansas City manager Mike Matheny also said he contracted COVID-19 a month ago and recovered during self-quarantine. He is now working on donating his antibodies.
On Friday, MLB and the MLBPA announced the first set of results for COVID-19 testing, publishing that just 1.2% of samples collected found positive tests or 38 tests out of 3,185 samples. The league said that of those 38 positive tests, 31 came from players and seven resulted from staff members. The tests were administered prior to the workouts and full baseball activities, which began Friday.
If a player tests positive for the coronavirus, he must test negative twice at least 24 hours apart, with no fever for 72 hours, before he can rejoin a team.
Other MLB players who have contracted the virus include Padres outfielder Tommy Pham and Indians outfielder Delino DeShields Jr. Both were announced Friday.