PITTSBURGH -- Over the past two days, the Pirates have made steps toward finalizing their Opening Day roster.

On Sunday, the Pirates added catcher John Ryan Murphy to their 40-man roster. They also selected the contract of left-hander Robbie Erlin on Monday. Additionally, they placed right fielder Gregory Polanco on the injured list.

None of those moves should be considered a surprise. Murphy was bound to make the team as Jacob Stallings’ backup catcher after Luke Maile underwent season-ending surgery on Friday to repair a fractured right index finger. Murphy joined the Pirates in Spring Training as a non-roster invitee on a Minor League contract, so the Bucs had to add him to their 40-man roster to put him on the 30-man active roster.

Similarly, Erlin signed a Minor League deal with Pittsburgh last offseason and came to camp as a non-roster invitee. The left-handed reliever’s results have been uneven in Spring Training and Summer Camp, but the Pirates are confident he’ll improve based on the work he’s done since joining the organization. Assuming Steven Brault is used as a traditional or tandem starter, Erlin and Nik Turley are the only left-handed relief options remaining in Bucs camp.

“Right at the end of [Spring Training] 1.0, we started to see the effects of the plan that we were putting into place, the adjustments that we were doing,” manager Derek Shelton said. “At the beginning of 2.0, there was a little bit [of a] step back, and I think we had to have some conversations about what we wanted him to do and how we wanted him to do it. In the last few outings, he’s really executed that. Really happy with that and happy he’s going to be part of the club.”

Shelton said the Pirates are “still waiting” to finalize their roster. They’ll have to select the contracts of a few other non-roster players who are expected to crack the 30-man squad, including left-hander Derek Holland -- who is in line to start the club’s home opener -- as well as super-utility man Phillip Evans and Turley.

“We still have a few days left to make a decision,” Shelton said.

Polanco recently gave the team permission to announce that he tested positive for COVID-19 and has reported no injury, so he was presumably placed on the COVID-19-related injured list, not the 10-day IL. It’s a key difference, because the COVID-19-related IL requires no minimum or maximum placement, meaning Polanco does not have to remain on the IL for 10 days if he is deemed healthy before then. Pittsburgh’s starting right fielder can return as soon as he tests negative twice at least 24 hours apart and is cleared by doctors.

Major League Baseball has instituted a COVID-19 list this season, although clubs will not announce which players are placed on it due to privacy laws regarding individuals’ health. Players may address their status if they wish, though they are not required to do so. Merely being placed on an injured list without further explanation is not confirmation that a player has tested positive for COVID-19. For example, potential exposure to a person who has the virus can be sufficient cause.

Pirates general manager Ben Cherington said during the AT&T SportsNet Pittsburgh telecast of Saturday’s exhibition game at PNC Park that Polanco is asymptomatic and “feeling great” with “no issues at all.” Since going on the injured list, Polanco has posted videos on his Instagram account in which he is working out inside his home, doing squats and swings with a kettlebell and various exercises with resistance bands.

“He's just going to have to be patient and get through the protocol,” Cherington said on Saturday’s telecast, “and he'll be back before we know it.”