The club released a statement on Monday saying their newly-acquired guard is not expected to participate in pre-season games this week after suffering a strained adductor muscle — inner thigh — during training camp last week in Halifax.
The Raptors say Lowry will undergo therapy and rehabilitation and there is no timetable for his return to full basketball activity.
Lowry was acquired in a off-season trade with Houston in exchange for forward Gary Forbes and a protected draft pick. He averaged 14.3 and 6.6 assists in 47 games with the Rockets last season.
The Raptors open the pre-season versus Real Madrid on Monday night at the Air Canada Centre.