England centre-back Stones continues to be heavily linked with a move to Chelsea, despite repeated warnings from Everton that he is not for sale, before the September 1 transfer deadline. The Toffees are believed to have rejected three bids for the highly-rated 21-year-old from Chelsea, the most recent of £30million. Everton goalkeeper Tim Howard has been impressed by the unflappable performances of team-mate John Stones amid considerable speculation over his future. Press Association Some players might be affected by such attention but Stones appears to be taking it in his stride, delivering another composed and mature display in defeat against Manchester City on Sunday. Howard said: “John is a different character (to some others). He is not arrogant. The most important thing for him is to play football and that is what he continues to do. “It is no surprise to me that his performances have been good. I think he is playing well.” Manager Roberto Martinez also continues to speak highly of the youngster and is determined not to lose him, even though he is poised to bring in a new defender in Argentinian Ramiro Funes Mori. Martinez said: “It puts a smile on your face when you see someone like John Stones defending the way he defends, getting on the ball the way he does. “He is an incredible footballer and to be able to organise things and control things at such a young age shows you the type of footballer he is. I thought he was outstanding once more (against City). “We have seen John grow in the last two years and we want to be as strong as we can when the window closes. We have our own aims and objectives and want to become a winning team.” River Plate defender Funes Mori, 24, watched Sunday’s game from the stands at Goodison Park and Martinez said afterwards a deal was close.