England coach Gareth Southgate is unsure whether Chelsea pair Conor Gallagher and Mason Mount can play together.
Southgate has warned Thomas Tuchel that playing the pair together could leave Chelsea "vulnerable."
The Three Lions boss played the two midfielders together during Saturday's 2-1 victory over Switzerland and admitted that his decision in the friendly match contained an element of risk.
Southgate suggested that the Blues could well find themselves in that predicament next season when Gallagher, who put in a shining display at Wembley, returns from his loan at Crystal Palace due to both being attack-minded players.
"We feel that Mount and Gallagher are very good at pressing and are two attacking 8s," the England manager told Sky Sports post-match. "But we know that that system can leave you a bit vulnerable to the switches to the opposite full-back and the Swiss worked that out very well – which is why we made the change of shape in the second half.
"But we had an idea of what we wanted to do, and although we would have liked to have Bukayo Saka and a couple of the other wing-backs to look at that, I still think it was worth seeing."