"He was part of that exposure that they talked about," Baker said. "That's what that was, part of the precautionary exposure and hopefully we'll get some news tomorrow."
All of the Astros' major league pitchers and staff members who had been working on the visiting side of Minute Maid Park were tested for the coronavirus, Baker said.
Despite scheduling hiccups in the past week, the Astros want to play a nine-inning simulated intrasquad game Monday, but that will depend on the latest COVID-19 test results.
Bench coach Joe Espada said Sunday that ideally, the Astros would play three to four games this week in preparation for the season's start, which for the Astros is scheduled for July 24 against the Seattle Mariners.
The Astros were back on the field Sunday after being forced to cancel Saturday's workout because of the staff member possibly being exposed.
Still, the Astros coaches who spoke with reporters Sunday seemed upbeat, even with the frustration of losing an entire day's workout.
It was the second practice they canceled since Monday, when COVID-19 test results did not arrive in time for them to take the field.
"It definitely affects (our daily routine), but we're doing what we can do with the people we can do it with, the people who are available," Baker said. "So, we've got to continue to get the guys ready who are here. The guys have a great attitude about things, no complaining. Everybody who was supposed to show up, showed up.
"You don't like it, but at the same time, you have to adjust. You have to make the best of a potentially bad situation and I'm proud of the guys on how they've responded."