Richard, who hasn’t pitched since July 13, has been limited to just 10 starts (45 1/3 innings) this season.
Richard missed the first eight weeks of the season with a stress reaction in his right knee, and the last seven weeks with a left lat strain.
The 35-year-old is 1-5 with a 5.96 earned-run average with Toronto.
The Blue Jays also announced Monday that left-hander Thomas Pannone was recalled from triple-A.
The announcements came before Toronto opened an interleague series in Atlanta Monday afternoon.