Sweeney was optioned to Triple-A Buffalo following Sunday's 9-1 loss to the Tigers, Shi Davidi of Sportsnet.ca reports.
Sweeney was summoned from the bench as a defensive replacement late in the blowout loss Sunday, representing his first big-league action since 2015. The 27-year-old's potential return to Toronto will get a little easier after he was added to the 40-man roster Friday, but he's unlikely to be anything more than a lightly used bench bat the next time he receives a cup of coffee.