Everton defender John Stones was named in the starting line-up for the Merseysiders' English League Cup tie at Barnsley on Wednesday, just a day after handing in a transfer request following repeated interest from Premier League champions Chelsea.

Stones is Chelsea manager Jose Mourinho's top target as he seeks to bolster his defensive options, but Everton have rejected three offers for the England international and he has now taken matters into his own hands.

After Chelsea's latest bid of £30 million ($47 million) was snubbed by the Goodison Park outfit, Stones is widely reported to have formally expressed his desire to leave before training on Tuesday.

However, Everton have been resolute in their determination to hang on to the 21-year-old and manager Roberto Martinez has insisted throughout the saga the centre-back is not for sale.

Wednesday saw Stones -- who joined Everton from Barnsley for £3 million in January 2013 -- selected by Martinez for the second round clash against his old side as one of two senior centre-backs alongside Phil Jagielka.

"I think what's important is that these games we need to be well-balanced, fresh and get the right combination, and a partnership in the centre-half position is vital for us," Martinez told Sky Sports before kick-off at third-tier Barnsley's Oakwell ground.

"Phil Jagielka and John Stones are really, really important in being able to have a good performance.

"We wanted to have this sort of a squad. The numbers that we have in the group now allow us some competition for places and we're going to have nine full internationals in the starting line-up, which gives you a little bit of an idea of the strength of our squad.

"Clearly John and Phil are a big part of that line-up."