Well yeah I understand that. I mean why would we risk waiving a guy we want in the lineup a week later? He would still be waiver eligible regardless as far as I know
Three main reasons:
1) Players who have already cleared waivers are waiver exempt until they play 10 NHL games or are on the NHL roster for 30 days. This is cumulative, so for example: if we called up Max McCormick and he played 6 games with us, we wouldn't have to expose him to waivers to send him back down. But if we called him up again and he played another 5 games with us, that is 11 total games, and we would have to place him on waivers again. Note: this doesn't mean that we CAN'T put him on waivers again if we wanted to. Example: if we called Hammond up because Condon got hurt or something, even if Hammond ended up backing up Andy the whole time and never played a minute, even though he's waiver exempt, we can still place him on waivers if we want in case we think someone might claim him.
2) players who have cleared waivers are allowed to be called up and send back down without having to clear waivers again
if it is on an Emergency Recall (ie: replacing an injured NHLer on the mail roster). Under the CBA, the player called up can spend up to 10 games or 30 days on the NHL roster on an emergency recall without having to be subjected to waivers again,
and these games don't count towards the 10/30 threshold of point #1 above. So it serves as injury protection for a team - you know there's a guy you can trust to play NHL minutes on your AHL team, you can stash him there in case someone gets hurt without having him count against the cap, and it doesn't even count towards regular waiver eligibility games.
3) You can waive a guy but not send him down. When a player clears waivers, you can still keep him on the NHL roster (there's no rule that you HAVE to send a player down after he clears waivers), and he is still waiver exempt until he plays 10 NHL games or is on the roster for 30 days. This tactic has been used before by NHL teams in pre-season who want to buy a bit of extra time to evaluate their guys. Waive a guy early in preseason, but keep him around and you've bought yourself a month to figure out what you actually want to do with him. In 3 weeks, if you want to send him to the AHL? He's already cleared waivers and still has another week of waiver exemption - just send him down, no risk.
CBA: 13.5 Waiver Expiration.
The rights granted under this Article to Loan a Player(s) who is otherwise required to clear Regular Waivers to a minor league club expire for any Player(s) who, after clearing Regular Waivers:
(i) is not Loaned to a minor league club, or is Recalled from a minor league club (except on emergency Recall) and remains on an NHL roster for thirty (30) days (cumulative) or plays ten (10) NHL Games (cumulative), or
(ii) is Recalled from a minor league club on emergency Recall and plays in ten (10) NHL Games (cumulative) while on emergency Recall. For purposes of clarity, games played while on regular Recall shall not count towards the ten (10) NHL Games in this subsection (ii).