If the Caps decided to trade McMichael, I don't think it would be for another prospect. I think they'd bundle him with more futures, like their first rounder, and dangle that package for an impact veteran forward who either has term remaining or who'd re-up as part of the trade. Someone like Horvat, for instance.
If there are those who wonder why the Caps might consider going in what seems like the wrong direction, given their season to date, the strong likelihood is that the team isn't going to rebuild until Ovechkin hangs them up. They want to keep trying to surround him with talent.
They see this season as a campaign shredded by injuries so far, and not a season felled by an aging core. Truthfully, it's probably a little of both, but they've been missing Backstrom, Wilson, Brown, and Oshie for most of the season up front. That's four of their top six. Some of those guys won't be coming back, are still out for a long time, or may be returning soon. Carlson and Orlov have also missed a great deal of time. Fehervary is their only other defender worth much (you can make a decent argument for Jensen). They might be aging, but the fact that injuries have overshadowed their season means they haven't been able to prove or disprove the aging-core thesis.
All things being equal, the plan is that McMichael replaces Eller at No. 3 center next season. There was going to be a center slot open, once Backstrom went down, but they plugged it with Strome.