Red Sox starter Tanner Houck has been added to the restricted list because he is unvaccinated for COVID-19 and is ineligible to play in Toronto. Steven Senne/Associated Press

The Red Sox placed pitchers Tanner Houck and Kutter Crawford on the restricted list before the first game of their series against the Blue Jays on Monday, the team announced. Right-handers Tyler Danish and John Schreiber were called up from Triple-A to fill the empty roster spots.

Both Houck and Crawford are not vaccinated against COVID-19, so they are ineligible to play in Canada this year, per the country’s rules. The Red Sox play again in Toronto from June 27-29 and Sept. 30-Oct. 2 for a total of 10 games at Rogers Centre in 2022. Unless things change, Houck and Crawford (as well as any other unvaccinated players the Red Sox add to the roster) will have to sit out those games. Every other player on Boston’s active roster is vaccinated and therefore eligible to play road games against the Blue Jays.

Houck and Crawford will not receive pay or service time during Boston’s four-game series in Toronto. Left-hander Chris Sale is also unvaccinated but is already on the injured list with a stress fracture in his right rib cage and wasn’t going to be ready for the series anyway.

Houck, who is 1-1 with a 2.87 ERA in four appearances (three starts) this year, won’t be able to take his turn in the rotation against the Blue Jays. Instead, after coming out of the bullpen Sunday against the Rays, he’ll likely start Boston’s series opener in Baltimore on Friday. Nathan Eovaldi, Nick Pivetta and Michael Wacha will start the first three games in Toronto with Garrett Whitlock likely to start Thursday’s finale.

Houck previously disclosed his vaccination status in an interview with The Boston Globe. He called it a “personal choice.” Last week, he said he has tried to avoid paying attention to any backlash regarding his decision.

“I’ve tried to stay away from it. No matter what side of the fence you’re on, there’s always going to be positive and there’s always going to be negative. I’ve got a job to do and focus on what I’ve got to do,” Houck said.

Crawford shined in spring training and was a surprising addition to Boston’s Opening-Day roster. A starter throughout his time in the minors, the righty has been used as a multi-inning reliever so far this season and has totaled a 9.00 ERA (7 earned runs in 7 innings) while striking out 11 and walking six. He is a candidate to be optioned to Triple-A Worcester when rosters shrink from 28 players to 26 on May 2.

Danish (five strikeouts in three scoreless innings) rejoins the Red Sox after being sent to the minors before Sunday’s game. Schreiber made one appearance for Boston last year (one earned run in three innings vs. Cleveland on Sept. 5) and owns a 1.74 ERA in 10 1/3 innings (five appearances) with the WooSox this year.

Houck and Crawford don’t count against Boston’s 40-man roster during the club’s time in Toronto. Schreiber will temporarily be added to the 40-man roster then removed once the series is over.