John Stones
John Stones has developed into one of England's finest centre-backs since joining Everton from Barnsley 2013 Getty

Roberto Martinez insists he is unaware of any transfer request from John Stones as the highly rated Everton defender continues to be linked with a late summer move to Premier League rivals Chelsea.

Stones, 21, has impressed hugely in recent times with the consistency of his performances alongside captain Phil Jagielka and provided a timely reminder of his quality with an assured display during the comfortable 3-0 victory over Southampton at St Mary's last weekend.

Although Manchester United have also been credited with an interest, Chelsea have long been considered leading suitors for the England international. The Guardian report that a third offer for his services worth £30m ($47m) was rejected last week and recent speculation from The Sun had suggested that Stones was set to notify Everton of his desire to leave the club and further his career elsewhere.

Martinez has always maintained that he is not for sale, however, and replied "Not at all, no" he said to the BBC when questioned if he knew of any such imminent plea ahead of his team's third match of the season against early league leaders Manchester City on 23 August.

While Everton remain eager to resist any further offers for their top assets, it appears they are now in a position to strengthen their squad with at least two new additions before September's transfer deadline.

"There are a couple of signings that are well in advanced stages," Martinez added. "We are looking for those two or three players. The game against Villarreal gave us a clear idea of what this squad needs in order for it to be as strong as it can be for the next 10 months. We are still in that period."

Although Martinez practiced what he has persistently preached with regards to Chelsea's three bids for Stones and did not reference his potential new signings by name, one player who could feasibly be making his way to Merseyside over the next few days is Andriy Yarmolenko.

According to Sky Sports, Everton have agreed a £15m fee for the Ukrainian winger having seen his talents first-hand during their 6-4 aggregate defeat to Dynamo Kiev in the knockout stages of last season's Europa League. Yarmolenko would be the fifth player to arrive at Goodison Park this summer following former loanee Gerard Deulofeu, Mason Holgate, David Henen and Tom Cleverley.

Everton welcome City this weekend more in hope than expectation, following the latter's impressive consecutive victories over West Brom and Chelsea, although Martinez revealed that the club's injury situation is certainly progressing in the right direction.

"From the squad that travelled to Southampton, we had no knocks or bruises," he told reporters. "We had very positive news on Kevin Mirallas, with whom we had to be a little bit cautious. He was ready to be involved if needed, but after that challenge against Watford, he wasn't 100%.

"He will be 100% going into the game at the weekend. Things are really positive in these areas – Darron Gibson, Tony Hibbert and Steven Pienaar are making good progress and, as you saw, Gerard Deulofeu and Muhamed Besic were on the bench [at Southampton]. Aiden McGeady was part of the travelling squad, so we have good numbers. Leighton Baines is right into the rehab programme that he has and everyone is progressing really well."