The 47-year-old Leiper crossed paths with general manager Alex Anthopoulos when the two were working for the Montreal Expos. Leiper worked in almost every level of the Minor Leagues before transitioning to a front-office position.
Toronto is expected to announce the move next week. Leiper would round out manager John Gibbons' on-field staff, which also includes new hitting coach Kevin Seitzer as well as returnees Pete Walker (pitching), Pat Hentgen (bullpen), Luis Rivera (third base) and DeMarlo Hale (bench).
Anthopoulos recently mentioned that the Blue Jays are considering adding another coach, but no final determinations have been made.
Gregor Chisholm is a reporter for MLB.com. Read his blog, North of the Border, and follow him on Twitter @gregorMLB. This story was not subject to the approval of Major League Baseball or its clubs.