Yep, you can do this with the GCMM homebrew app.
From the Dolphin Memory Card Manager, export the save game to GCI. Copy the GCI file to the SD card. Start GCMM on the Wii and copy the GCI file from the SD card to the memory card.
From the Dolphin Memory Card Manager, export the save game to GCI. Copy the GCI file to the SD card. Start GCMM on the Wii and copy the GCI file from the SD card to the memory card.
