The number of positive tests in the St. Louis Cardinals' COVID-19 outbreak grew to 13 on Monday, Major League Baseball announced. Seven positive tests were from players and six were from staff members. The league postponed St. Louis' four-game series against the Tigers that was scheduled to run Tuesday-Thursday after the latest round of testing.

The Cardinals did not play their weekend series against the Brewers after learning of multiple positive tests late Thursday night. They now will have seven games in a row postponed due to the outbreak. MLB is still planning on the Cardinals playing the Cubs on Friday.

The Cardinals are the second MLB team dealing with an outbreak in a season that is not yet two weeks old. The Miami Marlins had four players test positive last weekend, and that number grew to 18 over the course of the week.

Another concern is whether the Cardinals spread the disease to the Minnesota Twins, their opponents and hosts earlier this week. The Twins have not had anyone test positive and were on the field for a four-game series against Cleveland that started Thursday. If there is good news in that regard, it's that team-to-team transmission during a game seems unlikely.

The Philadelphia Phillies, who played a series against the Marlins, have not yet had a player test positive, the team announced on Saturday.