Yeah, if you're going to do this, it's optimal - but only slightly so - to redshirt at the end of the season, so he grows a little more in attributes (if applicable) and IQ. With bottomed out WE, he will sit like a bump on a log all season. That won't matter a whole lot, he may already be maxed or close on everything important, and for IQ, it will only be the difference of half a grade at most. But it's not nothing. I'd recommend as soon after the conference tourney as you can, if you go this route, so you don't forget.
The biggest downside for me is that I am likely to forget about him and just let him walk at the end of the season. I usually have to set some type of reminder to remember when to actually apply the redshirt, and even reminders don't typically help me much because I usually just turn them off. So for me personally, if he's important to next season's plans, which is really the only reason I consider this move seriously, I will tend to apply the redshirt toward the middle of the season, rather than wait until the last possible moment. He won't leave, as the system stands right now, so no worries there.