Manor insists the signing of Fabio Leimer to a reserve driver role does not mean Roberto Merhi is in danger of losing his seat.
Manor announced the arrival of the 2013 GP2 champion last week, just days after former Mercedes technical director Bob Bell joined the team as a consultant for the rest of the current season. Though Will Stevens is contracted through to the end of the year Merhi's deal is less long-term and has been confirmed on a race-by-race basis since the Spanish Grand Prix.
The signing of Leimer led to speculation Merhi could be on borrowed time but Manor has stressed that is not the case.
Asked if Merhi's days at Manor were numbered, sporting director Graeme Lowdon told F1i: "No, not at all. We'd been running without a reserve driver and although we have various arrangements in place to cover that situation, it's better to have that sort of area covered with someone who's with the team all the time.
"These cars are so complex now, it's not a case of just strapping someone in. So there are huge advantages to having a third driver and yes, you're quite right, it keeps everyone honest and there's no harm in that. These guys all know each other and feed off each other and the other thing is that with the way regulations are going it's harder to find the right drivers with the right experience."
Canada was the first time this year Merhi out-qualified team-mate Stevens. He had beaten him on track for the first time in Monaco and looked set to do so again in Canada before a driveshaft issue forced him to retire.