Ross Barkley joined Everton at the age of 11

Everton midfielder Ross Barkley will have to add to his game if he is to reach his potential at a top-four club, says former Toffees player Leon Osman.

Everton boss Ronald Koeman says Barkley is "looking for a new challenge" - and Tottenham are reportedly interested in signing the 23-year-old.

"He is certainly going to get into top teams in the league," said Osman.

"But he's not got the all-round game yet that managers of these top four or six clubs want to see."

Speaking on BBC Radio 5 live, he added: "Moments of brilliance he shows are what clubs strive for. That's why he's constantly linked with top clubs. Not every player can produce those moments."

Osman believes the timing of Barkley's decision is odd in a summer during which Everton have spent heavily on 12 new recruits.

He was not part of the squad for Thursday's Europa League qualifier win over MFK Ruzomberok, and on Friday he was linked with a move to Premier League champions Chelsea. external-link

"Ross Barkley has got a big decision to make," Osman added. "Now it's up to Koeman to plan for time without him.

"He has to plan for the club to move forward and he's been doing a good job so far."

Move could refine Barkley - Upson

Barkley '100%' will leave Everton - Koeman

Barkley, who joined Everton aged 11, scored six goals in 39 appearances as Koeman's side finished seventh in the Premier League last season.

He featured in 36 of their 38 league games but his future was a regular topic of conversation at Koeman's news conferences during the second half of the campaign as the England international failed to agree an extension to his contract, which expires in June 2018.

Spurs, who are yet to make a signing this summer, have been linked with him and former Arsenal defender Matthew Upson believes a move could improve Barkley's game.

"I think Ross Barkley has the potential to be a top four player," he told 5 live. "That's the key. If he went to Tottenham, Mauricio Pochettino could give him things he needs to be that top-four player.

"Some of the things you see in him at times, you think if you could hammer things into him, you could have a top player."

Everton above Liverpool?

Osman believes Everton's summer signings, including midfielder Davy Klaassen from Ajax, striker Wayne Rooney from Manchester United and defender Michael Keane from Burnley, mean a top-six finish should be a minimum goal.

Manchester United finished eight points clear of Koeman's side in sixth last season, while their Merseyside rivals Liverpool were a further seven points better off in fourth.

Asked if Everton could finish above Jurgen Klopp's side in the 2017-18 campaign, Osman said: "Absolutely. The divide isn't that big with regard to the league.

"I think Everton seem to be not capable of beating Liverpool enough times when it's head to head. But over the course of the season points-wise there isn't much in it.

"A top six and improving is the aim and any kind of silverware. Everton have waited a long time. They say you get the first one and more will follow. Everton are desperate for that at the moment."