Foreign nationals who aren't vaccinated against COVID-19 are not allowed to enter Canada, save for limited exceptions that require a 14-day quarantine. Unvaccinated baseball players are placed on the restricted list, where they are not paid and do not accrue major league service time.
Chafin signed a two-year, $13 million contract with Detroit in March. He will lose $142,857 from his $6.5 million salary this season.
Detroit selected the contract of right-hander Bryan Garcia from Triple-A Toledo as a substitute player and added right-hander Derek Law and shortstop Zack Short to its taxi squad.
Chafin had a career-high five saves and 64 strikeouts in 71 games in 2021, splitting the season between the Chicago Cubs and Oakland. His 1.83 ERA ranked fifth among major league relievers.
Garcia is 5-3 with a 6.12 ERA in 72 relief appearances over the past three seasons. He's scheduled to make his first career start Friday against Blue Jays All-Star right-hander Alek Manoah.
Garcia was 1-2 with a 2.90 ERA in 31 games at Toledo, including three starts.
"He's done a nice job all year," manager AJ Hinch said. "Probably should have got a chance in our 'pen, but we haven't had any openings."
Hinch said Law, who pitched for Toronto in 2019, will likely be added to the roster over the weekend, possibly in response to Detroit trading a relief pitcher to a contender ahead of Tuesday's deadline.