On Sánchez, City Passes and United Strikes

Alexis Sánchez is set to be on his way from Arsenal to Manchester United.MANCHESTER, England — Arsène Wenger knew what would happen, and he knew it would hurt.

In the summer of 2012, after several tense telephone conversations between Wenger, the Arsenal manager, and his longstanding rival, Alex Ferguson of Manchester United, Wenger agreed to sell his club’s prized asset, the Dutch striker Robin van Persie, to Ferguson’s team. The deal cost Ferguson $34 million. It would cost Wenger substantially more.

The transfer proved a masterstroke for Ferguson, in the short term, at least. The previous season, a goal from Sergio Agüero in the final minute of the final game had handed Manchester City the…