Surely the fatigue is cumulative though?
So say we went full strength here v Dortmund and got a bit better result meaning we had a chance in the 2nd leg. So then we play Villa, but we still put out a pretty strong team. And then we go strong again at home v Dortmund (we'd have to, or first leg effort would be pointless). And then we go pretty strong again v Bournemouth. That's a tough effort, and then comes league games against Liverpool away and Man Utd at home.
I think Poch recognises we need to win these next two league games to stand a chance at the title, and he's prepared to sacrifice the Europa to increase the chance of that happening. It may not work out that way, nothing is certain. But given this season, it's the right call imo.
Every man and their dog are saying how big of an advantage Leicester have, just able to focus on the league. Well now we can. And I'd take 1 league title over 100 Uefa Cups.