Chelsea Transfer News: Latest Rumours on Diego Costa, Paul Merson Comments

Everton manager Ronald Koeman has refused to rule out an audacious swoop for Chelsea striker Diego Costa.

David Wright of the Daily Express reported the Toffees are searching for a replacement for Romelu Lukaku before the close of the transfer window on Thursday, and Costa could be the surprise name that arrives on Merseyside.

Koeman was cautious with his words as he discussed the controversial Spain international:

"I don't know [about Costa]. We are looking at players who are available and if we sign somebody, it is somebody who makes the team better.

"I don't speak about names, about players. It is the media who is talking about Costa or other players.

"But we are looking and we do our job and hopefully, we will arrange it [a striker to arrive] for next week."

Robbie Jay Barratt - AMA/Getty Images

According to Chris Bascombe of the Telegraph, Costa has refused to return to training with the Premier League champions while his exit from Stamford Bridge is negotiated, with Koeman saying he would "welcome" the chance to purchase the player.

Costa scored 20 goals in 35 Premier League appearances last season, according to Squawka, and his reputation in front of net remains undiminished.

Everton would be a surprising switch for the Brazil-born attacker, but if his Chelsea career is over, he might need to take a transfer simply to depart west London.

In other Blues news, former Arsenal and England forward Paul Merson has said Chelsea must buy a centre-back and a striker before the transfer window closes.

Frank Augstein/Associated Press

Speaking to Sky Sports, Merson said European football will seriously affect Chelsea's ability to retain the title and remain consistent this term:

"They still need another centre-forward and centre-half with the extra games they're going to have to play. They've got the money to go and get Virgil van Dijk or they could even go for Jonny Evans, who I like.

"Strikers are hard as everybody wants one but if Alvaro Morata gets injured is Michy Batshuayi going to fire you to title? He's a decent player but I'm not sure he's at that level.

"Pierre-Emerick Aubameyang is one that has been mentioned but I'm not sure he's got that physical presence to lead the line on his own so it's a difficult one."

Catherine Ivill - AMA/Getty Images

Costa's absence from the first team has left the Blues short of quality up front, and they lack the fluidity they had 12 months ago.

The Blues won the title with a relatively small squad last season, but they will not cope with the fixture congestion generated by the UEFA Champions League this term.

Manager Antonio Conte will be frustrated by the lack of business completed by the Stamford Bridge board over the summer, while Chelsea's main rivals have strengthened in multiple positions.

Manchester City and Manchester United have revamped their selections, but Chelsea have been weakened after the exits of John Terry and Nemanja Matic.