Well as others have pointed out, you'd really only need it if you anticipated renting some sort of vehicular conveyance. If you don't think you're going to be renting mopeds or a car, then I'd say wait until you get back.
I'm not sure if Manitoba is like Saskatchewan in this sense, but in Saskatchewan you have the paper driver's license and then a plastic identification card. I can't see them saying the plastic ID isn't valid even if you no longer drive or possess a valid driver's license.
From SGI's website:
"A photo identification card is available from SGI for all residents of
Saskatchewan, regardless of whether or not the individual is a licensed
From the MPI site here
, it looks like Manitoba is the same way.