BOSTON -- Red Sox manager Alex Cora tested positive for COVID-19 shortly before Thursday’s 3-2 loss in the series finale against the Blue Jays at Fenway Park. Cora, who is fully vaccinated and boosted, is experiencing mild symptoms. Bench coach Will Venable managed in Cora’s place on Thursday.

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Earlier this week, Kevin Plawecki and two staff members tested positive prior to Monday’s Patriots’ Day game against the Twins. Plawecki, who is vaccinated, is said to be making good progress, and Cora didn’t rule out the catcher getting activated within the next couple of days.

Infielder Jonathan Araúz is also on the COVID-19 IL after testing positive on Tuesday. Christian Vázquez had a brief stint on the COVID-19 IL this week, testing positive Tuesday before he was activated on Wednesday.

Boston is navigating this COVID-19 outbreak amid a stretch of 13 consecutive games against American League East opponents. After hosting the Blue Jays for three games, the Red Sox head to St. Petersburg to open a 10-game road trip that includes a stop in Toronto.

With a vaccine mandate in effect in Canada, players must be fully vaccinated -- which is recognized as having received two doses of the Pfizer or Moderna vaccine, or one dose of Johnson & Johnson -- in order to travel to Rogers Centre.

Earlier this week, Tanner Houck, who allowed two runs on three hits while striking out four in his five-inning start Thursday, told The Boston Globe’s Julian McWilliams that he is not vaccinated. His next turn in the rotation would be Tuesday, the second game of a four-game set in Toronto.

With players on the COVID-19 IL and Houck unable to travel to Canada, the Red Sox have made a number of adjustments this week. Cora confirmed that other players will also be unable to travel due to the vaccine mandate, but he did not say which players or how many fall into that category.

“Obviously you want everyone to be there, the whole team, your teammates,” Xander Bogaerts said. “But it’s a personal decision, and you can’t force anyone to do what they don’t want to do.”

“We just have to make adjustments, that’s it,” Cora said Thursday morning. “From my personal perspective, you know, you gotta respect their decisions [about getting the COVID-19 vaccine], and we have to adjust. That’s the bottom line. Obviously, it’s not perfect, but it’s where we’re at. And going into Toronto, this is what it’s gonna be now, and it’s probably going to be the rest of the season.”

Here’s how the Red Sox’s arms line up for their three-game series vs. Tampa Bay:

Friday: Michael Wacha
Saturday: TBD
Sunday: Rich Hill

Cora said Thursday that there’s a chance Garrett Whitlock will start Saturday, with a leash of three to four innings. In four relief outings this season, Whitlock is 1-0 with a 0.93 ERA, a 0.62 WHIP and a .121 opponents’ average. Hill’s turn was pushed back one day after the veteran lefty spent time on the bereavement list following the death of his father last Friday.

Since Houck will not be able to take his turn on Tuesday, Cora expects him to come out of the bullpen in the series finale, piggybacking off Hill. The Red Sox have not announced any starters beyond Sunday.

“I mean, any opportunity I have to go out there, I’m excited for,” Houck said of working out of the bullpen Sunday. “I love being on the mound, love being able to participate and just help this team in any way. So getting back out there Sunday, hopefully, I’m excited for it. And you know I’ve always said, whatever I can do to help the team win.”

With a shortened Spring Training and multiple hits to the rotation after Chris Sale (stress fracture, right rib cage) and James Paxton (Tommy John surgery) were placed on the 60-day injured list, pitching remained the biggest question for the Red Sox coming into the season. After allowing three runs in his 3 1/3-innings season debut, Houck has struck out eight and yielded just two runs in his past 10 2/3 frames.

“I felt like I’ve progressed a little bit in each one, in terms of just command, in terms of just stuff-wise,” Houck said. “Four-seam I felt like was really good today; that’s a pitch that I’d been struggling with a little bit. Giving too much arm-side run on it. But today, it felt really good. Definitely feel like I also started to really start feeling the slider again; that’s a big pitch for me. As well as throwing the splitter, I feel like that’s been kind of my best offspeed pitch this early in the season so far.”