He wasn't banned, sir. It was just a precautionary measure. The coronavirus has an incubation period of 14 days. So, the chap had to be put on watch to see if the virus would manifest. That plus the fact that if he traveled with the squad, he might have faced issues coming back because of EU measures to prevent spread of the virus.
Been a while sir
RE: Ighalo banned from training with the rest of the team over fear of Coronavirus contagion threat