Unrealistic given Atlético's inconsistent form this season, and Delaney has a chequered past in terms of potential United signings, but all for this move. Not the perfect fit with Bailly (that would be Laporte), but Giménez is a better defensive talent than every single one of our centerbacks (even Eric), and young enough to become a formidable tower of strength for the long term. A departure from the Rio/Vidić or Carvalho/Terry sweeper/stopper holy grail, but given some freedom, he's a strong vertical runner in possession:
A bit like peak Jones (in a good way) or young Leverkusen Lúcio - who admittedly had more tactical leeway than Giménez does under Simeone, and could forge an uncompromising Lúcio-Samuel type combination with Bailly, with both equivalent pieces being much younger. His distribution on the ball could be improved over time, and his decision-making is sometimes a bit suspect, but that will come with some experience. In terms of raw defensive ability - the thought of having two supremely athletic U-23 centerbacks with world class talents is super enticing. Put a good DLP ahead of that and you wouldn't really miss out on the distribution/ball circulation element, IMO.
Oh, and he's a nutter, which is a good personality fit with trademark Mourinho defensive lines.