The Tottenham forward began the tournament brilliantly with five goals in two games but his form tailed off in the knockout stages, and he was particularly anonymous against Croatia in the 2-1 defeat in extra-time.
And Neville believes he was masking an injury.
"I’d be amazed if he hadn’t been carrying an injury since the Colombia game," Neville said on ITV.
Against Sweden he was static. I’d be amazed if he doesn’t come out and something emerges about his fitness.