In the latest problems for Major League Baseball as it attempts to stage a season during the novel coronavirus pandemic, two Cleveland Indians pitchers entered quarantine after violating protocols, more games involving the St. Louis Cardinals were postponed, and a starting pitcher for the New York Mets opted out.

Pitcher Zach Plesac apologized after the Indians called a car service to take him home from Chicago rather than letting him fly home with his teammates after he violated team rules and safety protocols by going out Saturday night with friends.

“I realize I made a poor choice to leave the hotel, which broke protocols and could have endangered other people,” Plesac said in a statement. “I understand that in these times of uncertainty, I need to be more vigilant and responsible, and I am determined to earn my teammates’ forgiveness and get back to work.”

It is unclear whether Plesac had been tested, and he will be tested daily while being quarantined for three days. The team had yet to decide whether he would be disciplined for his decision during this compressed, 60-game season.

“We love Zach, we support him, but he screwed up,” pitcher Shane Bieber said (via ESPN). “We’re going to handle this in-house, and we’ll see where it goes from here.”

On Monday, the Indians announced that pitcher Mike Clevinger also will quarantine — causing him to miss his scheduled start against the Chicago Cubs on Tuesday — after the club learned that he violated safety protocols as well. According to ESPN, Clevinger accompanied Plesac on his night out.

Meanwhile, the Mets’ Marcus Stroman has opted out of the 2020 season. Stroman praised the team’s approach to safety protocols, but he said (via the Athletic) that seeing outbreaks elsewhere “makes you realize how hard it is to make sure that everything is buttoned up, 24/7, from every angle.”

And after another St. Louis player tested positive, the Cardinals’ series against the visiting Pittsburgh Pirates, which was to have run Monday through Wednesday, was postponed Sunday. On Monday, MLB announced that St. Louis’s doubleheader at the Detroit Tigers on Thursday also had been postponed. The Cardinals have not played since July 29; 17 members of the organization (10 players and seven staff members) have tested positive since last week.

Manager Mike Shildt revealed Sunday that some members of the organization have had to seek treatment in an emergency room after experiencing symptoms. John Mozeliak, the team’s president of baseball operations, said one player and one staff member had gone to a hospital, but neither was admitted for treatment and both are at home.

“There are people that have symptoms and have had a few visits to the ER for some IVs and a little more clarity,” Shildt said during an interview with KMOX Radio. “Nobody has had to stay [in the hospital]. But there are people dealing with — I mean, this is real. And people are experiencing a lot of the symptoms that we hear about, that are associated with this. A variety of them. Most of them are experiencing multiple ones. Seems like they rotate with them. And, again, nobody is in close to any critical shape, but people are having to deal with some things that aren’t comfortable at all.”

Since the MLB season began July 23, 29 games have been postponed because of coronavirus concerns. MLB has responded by placing stricter rules on players and staff on and off the field.

For Mozeliak, that meant the team is “doubling down on our tracing” in an effort to get back on the field.

“It’s a bummer. We’re learning as we go,” he told reporters. “What’s the right amount of time to not assemble to try and prevent the spread? I don’t think we know that answer perfectly.”