ST. LOUIS -- After five days quarantined in their downtown Milwaukee hotel, after learning that nearly a fourth of their roster and a significant portion of their staff had tested positive for COVID-19, and after having to rework the regular-season schedule to play 55 games in 52 days, the Cardinals received good news Tuesday evening.

They had been cleared to get back on the baseball field.

In the final step needed to leave their hotel and travel again, the Cardinals’ test results returned negative for the second straight day Tuesday. After 13 members of the traveling party tested positive for COVID-19 over the weekend and left Milwaukee to quarantine at home, the rest of the team will fly back to St. Louis around 11 a.m. CT on Wednesday, president of baseball operations John Mozeliak told reporters in a Zoom call Tuesday night. From there, the Cardinals will have workouts Wednesday and Thursday afternoons before resuming play Friday night against the Cubs at Busch Stadium.

It has been five days of growing concern and uncertainty, ever since the Cardinals learned of two initial positive COVID-19 tests late Thursday night after testing conducted July 29. That number grew to four confirmed by Saturday, and swelled to 13 by Monday morning, with seven players and six staff members infected.

As the number grew, the Cardinals were quarantining in their hotel rooms. They never played in Milwaukee and didn’t go to Detroit, instead pausing their schedule and hoping the outbreak was contained. The club understood the challenges of returning with the growing number of positive cases but never thought their season was over.

“I think my darkest moment was really, when you go back to Saturday or Sunday, when the numbers just kept going the wrong direction,” Mozeliak said. “You read the papers and you look at trends and you hear things about flattening the curve, and where’s that going? We were just going in the wrong direction. Now, our little world was just 57 people, but it still was tracking in a very frustrating manner to where I thought, ‘Oh gosh. This could actually get everyone here.’

“For the last couple days to just get this … good news in these test returns, it was just uplifting. I feel a lot better about things.”

Mozeliak was visibly relieved on Tuesday’s Zoom call, and rightfully so after taking an important step forward in resuming the season. The process doesn’t stop there, though, and Mozeliak said the team will continue to be tested daily and be even stricter with safety procedures like mask-wearing and social distancing.

“They realize the importance of what they just experienced, and they don’t want to do it again,” Mozeliak said. “That’s not to say it won’t happen again. But they don’t want a repeat.”

The urgency of quarantining was not lost on the team, even though being confined to a hotel room for multiple days had players, coaches and staff itching to get out. But the “luckiest” part of the entire situation, Mozeliak said, was the Cardinals’ off-day last Thursday, because the entire traveling party did not meet.

“I think that really changed our trajectory, which is scary, because we still had 13 positives,” Mozeliak said. “Had we had a game that day and treated it as a normal day -- which we would have, because we would have not known of those positives -- I think we would’ve been looking at … a very dramatic effect on this team. And 13 could’ve easily doubled.”

Challenges still remain. It will have been a week since their last game, and the roster will be missing seven players, including three All-Stars -- right-hander Carlos Martínez, catcher Yadier Molina and shortstop Paul DeJong. Molina and DeJong were two of six players to announce Tuesday that they tested positive.

With rosters reducing to 28 from 30 on Thursday, the Cardinals will fill four spots from their alternate training site in Springfield, Mo. If the team chooses, the players on the injured list can not count against the 40-man roster and replacement players can be added, but once the injured players return, those replacement players will have to be taken off the 40-man roster via a transaction. The Cardinals will also add to their 60-man player pool to fill out the depth in Springfield.

 “Obviously, some of the people that we put on [the injured list] -- they’re just hard voids to fill,” Mozeliak said. “But having said that, I’m not overly concerned about getting to a quality 28. I think once you get to that number, clearly there’s going to be some gaps.”

The other challenge will be to make up the lost time in an already condensed schedule. If the Cardinals play 60 games this season, they will need to play 55 games in 52 days. Doubleheaders -- reduced to seven innings this season -- will be frequent.

“It is possible,” said Mozeliak, who has seen a version of the reworked schedule. “All I can say is I’m so grateful for seven-inning doubleheaders. If we were doing nine, this would be a monumental task.”