Ronald Koeman reveals two key criteria for Everton's summer transfer targets

Everton manager Ronald Koeman thinks it will be difficult for the Toffees to keep Romelu Lukaku, a target for Chelsea, and has instead set his sights on recruiting offensive players between the ages of 26 and 29.

Lukaku has enjoyed a stellar season on Merseyside and is currently the Premier League's top scorer on 24 goals, four clear of Tottenham's Harry Kane. The Belgium international's form has caught the eyes of a host of clubs, and Koeman – who could not provide an update regarding Ross Barkley's contract situation – is facing a fight to keep the 23-year-old at Goodison Park.

"First of all we like to keep the best players but that's difficult, we know that," Koeman said in his press conference ahead of Everton's clash with Chelsea. "I don't know if it's possible to keep them. we have to analyse the team and what we need. We need offensive players more who score more goals, the difference between Lukaku and the rest is too big."

Koeman is set to bring in a host of fresh faces in the summer to help bolster his first-team squad, but he may not need to look too far for players who can strengthen the Blues.

Everton's Under-23s won the Premier League 2 title on Monday (24 April), and manager David Unsworth believes a number of the young starlets are ready to step up into the first team. Koeman, who has afforded opportunities to a host of youngsters this season, does not fully agree with 'Rhino', and is instead looking to sign players in their prime years.

"Sometimes I feel there is too much positivity about the young players," Koeman added. "I know they're not ready, I know how difficult it is to make the first step. Just because you win the [Under-23s] title doesn't mean you're ready. It's too easy to tell a lot of players that they are ready for the first team. It's not the case.

"It's impossible to have 15 young players in the first team, now we have enough young players in the squad and it's difficult because it's easy to come but difficult to stay. We need more players aged 26-29 to improve. Of course we stay open for young players, but little by little, they're not ready."

Koeman is intent on adding to his squad in the summer, but his immediate focus is on Everton's clash against Chelsea. The Toffees have won their last eight matches at Goodison Park and are seeking revenge on Chelsea, who dished out a 5-0 drubbing in the reverse fixture in November.