Former England striker Les Ferdinand fears a lack of depth in attack could prove costly to Gareth Southgate's side at the World Cup.

With Tottenham star Harry Kane sidelined due to an ankle injury, Jamie Vardy, Danny Welbeck and Marcus Rashford are the only dedicated forwards in the squad for this month's friendlies with Netherlands and Italy.

Ferdinand expects Kane and Vardy to be the obvious candidates to start when England begin their campaign in Russia against Tunisia on June 18, while he hopes Raheem Sterling and Adam Lallana can offer a threat from deeper positions.

However, the former Spurs forward admits he is worried by Southgate's lack of options for the number nine role.

"I'm not sure we have enough depth," he told Omnisport. "Obviously, the two outstanding candidates are Harry Kane and Jamie Vardy. Raheem is scoring goals for Man City but you wouldn't really have him as a striker, but there are other goals in the team as well.

"I like the fact that Lallana is coming back and by the time the World Cup comes around, he is always good for a goal or two. It's just that strength in depth really that we haven't got in the striking position."

Arsenal midfielder Jack Wilshere earned a recall to the squad for this month's matches and has been tipped to go to the World Cup, having re-established himself as an important part of the Gunners' central midfield.

Ferdinand feels the 26-year-old has benefited from a run of matches, something he also enjoyed on loan at Bournemouth last season, and he hopes to see Wilshere at his peak in time for Russia.

"He is playing on a regular basis," he said. "The reason why he went to Bournemouth last year was to get some games under his belt. He's got that, he is playing more games for Arsenal than he has in the past.

"Hopefully, come the World Cup, he will be fit and raring to go again."