Harry Kane's lethargic Euro 2016 performances have former England striker Alan Smith concerned that the Tottenham man's "legs have given up on him".
Kane has only mustered one shot on target in 135 minutes at the tournament and was replaced along with Raheem Sterling as Roy Hodgson made a half-time double substitution against Wales, with England trailing 1-0.
Jamie Vardy and Daniel Sturridge came off the bench and both scored as England snatched a dramatic last-gasp 2-1 victory in Lens to go top of Group B.
"Harry Kane looked shattered to me," Smith told Sky Sports News HQ.
"I think he has a long, hard season at Spurs where they do demand 100 per cent every week. They get through an awful lot of running. I hope I'm wrong but it looks like his legs have given up on him for this season.
"It could be [that he is burnt out]. I know what you feel like when you get to a tournament after a long season. Sometimes you're okay, other occasions you think, 'Oh my there is no energy left in my legs here'.
"You feel for Harry if that's the case because it's a big tournament for him. He's enjoyed a fantastic season at Spurs again, scored lots of goals, but that's what happens sometimes and somebody else comes from the fringes to makes themselves a hero.
"One thing is that we've got good options from the bench, which obviously Roy Hodgson used very well. In this tournament you need patience and persistence.
"A lot of the matches have been that way, there have been a lot of late, late goals in stoppage time and you've just got to keep plugging away."
Smith expects Hodgson to rotate his squad for Monday's game with Slovakia and thinks the England boss could use the clash to experiment with his formation and tactics.
He said: "It's a game we don't need to win but I think Sturridge and Vardy will play and that might mean he goes to a diamond in the way that he did in the second half against Wales, with Wayne Rooney just at the tip of it.
"Dele Alli hasn't really shown his Spurs form so far [at this tournament]. I probably expect him to stay in there.
"Jack Wilshere is kind of gnawing away at the edges to gain inclusion.
"He gives you something different and I'm sure Jack will play a part in this tournament.
"But we're in a nice situation, it's not desperate and we don't have to win."