AP photo by Jeff Roberson / Miami Marlins second baseman Isan Diaz became his team's first player to opt out this season due to the coronavirus pandemic, with his decision becoming public Saturday.

The coronavirus forced Major League Baseball's 17th postponement in 10 days on Saturday, prompting at least two more players to opt out for the season and casting doubt on a truncated 2020 schedule being completed as planned.

The Milwaukee Brewers' home opener against the St. Louis Cardinals was postponed for the second straight day after one more player and several staff members for the visiting team tested positive for the coronavirus in rapid samples, MLB said. The staff total of positives was three, a person familiar with the situation told The Associated Press; MLB said results of saliva tests would not be available until later.

Milwaukee then announced that center fielder Lorenzo Cain, a two-time All-Star and a 2019 Gold Glove winner, will not participate in the rest of the 2020 season. The Miami Marlins received no new positive results in their latest round of coronavirus testing, MLB said, but second baseman Isan Díaz also opted out.

The Philadelphia Phillies, meanwhile, were permitted to access their Citizens Bank Park for staggered workouts beginning in the afternoon. MLB said no Philadelphia players have tested positive for COVID-19 in the past week, and that while three staff members have tested positive, it appeared two were attributable to false positives and the third, based on the timing of the positive test, may not have contracted COVID-19 from the Marlins.

MLB rescheduled the Phillies' postponed games against the New York Yankees for Monday and Tuesday in New York and Wednesday and Thursday in Philadelphia. The Yankees' road game against the Tampa Bay Rays on Thursday has been rescheduled as part of a doubleheader on Aug. 8.

"What the virus has taught us is this is a day-by-day, week-by-week situation that we live in," Yankees manager Aaron Boone said.

Miami will play a four-game series against the host Baltimore Orioles this Tuesday through Thursday, with one game a doubleheader. The Marlins will be the home team for two games.

MLB said it will reschedule the missed Yankees-Orioles game and Marlins-Phillies series.

The people with knowledge of the Cardinals' and Marlins' situations spoke to the AP on condition of anonymity because the tests had not been released publicly.

Two Cardinals players were flagged for positive tests Friday, forcing the series opener in Milwaukee to be called off. The teams had hoped to resume play Saturday and make up Friday's game as part of a doubleheader Sunday.

St. Louis learned of its first two positive tests Thursday night from samples taken Wednesday before a game in Minnesota. Players and staff were instructed to isolate in their hotel rooms, and the club said it was conducting rapid testing and contact tracing.

The Cardinals have not been to Miller Park since arriving in Milwaukee, and the Brewers have not reported any positive tests among their players since the season began. Despite that, Cain informed management he no longer wanted to participate.

"We fully support Lorenzo's decision and will miss his talents on the field and leadership in the clubhouse," Brewers general manager David Stearns said in a released statement.

At least 21 members of the Marlins' traveling party have been infected by an outbreak at the start of a season-opening trip. The team hasn't played since last Sunday in Philadelphia but hopes to resume games in the coming week.

Díaz consistently tested negative while the season was on hold, but he decided to become the first Miami player to opt out. He played in two of the Marlins' three games before their season was halted.

"This has been a tough week to see so many of my teammates come down with this virus, and see how quickly it spreads," Díaz wrote on Instagram. "After much deliberation and thought, I have made the difficult choice of opting out for the remainder of the 2020 season."

Díaz batted .173 as a rookie last year, but the organization has big hopes regarding his potential.

Cleveland players and staff talked about postponing Friday night's road game against the Minnesota Twins but played on. The Cardinals played in Minneapolis on Wednesday, a day before the Indians arrived.