Roy Hodgson fears a successful run in Europe could deflect Fulham away from their primary target of Premier League survival.
Fulham follow up their League opener at Portsmouth tomorrow with the home leg, on Thursday, of their Europa League playoff against Russian side Amkar Perm.
The concern at Craven Cottage is that playing regularly in Europe will place a strain on Fulham's comparatively small squad, possibly with dire consequences domestically.
Manager Hodgson admitted: "It would be foolish of me to say there is no chance of that happening. I think the team are still strong.
We're even getting stronger if anything. But last year we were extremely lucky with injuries.
I don't know quite whether that will happen to us again."