I don't think there's a hard and fast rule, but as others have said, it's stupid as hell to game it around contract status by having him play 9 NHL games, send him to the ahl for a month, then have him sit around for ANOTHER month before the WJC.
Sure maybe he was nursing and injury or hitting the gym or whatever but its' like this organization is allergic to giving high skill players high skill/minute reps and they keep trying to reinvent the wheel, Clarke's is the weirdest I've seen maybe ever. Juniors to Europe back here to the NHL to the AHL to the WJC maybe back to juniors?