Jonas has already scored eight goals in 12 La Liga games this seasons. [Reuters]

Everton are set to offer £8m to sign Valencia striker Jonas Gonçalves in the next transfer window, reports in Spain claim.

With Nikica Jelavic struggling for form and Arouna Kone set to miss the rest of the season due to injury, manager Roberto Martinez has asked his club for a back-up striker to Romelu Lukaku.

Several Spanish media outlets claim Everton have been monitoring Brazilian Jonas since last summer and are now keen to launch an £8m bid to secure his services.

Considering Chelsea loanee Romelu Lukaku will only be at the club until next summer, the Toffees are already looking for a striker to add more options to Martinez's squad. The 29-year-old can play both behind Lukaku and as the main striker.

Last month it was reported that Valencia were considering selling Jonas after a difficult start to the season. However, in the last few games he has became a key player for the Spanish team and they are now set to keep him unless they receive a vast amount of money.

Jonas cost Valencia just £1m from Brazilian club Gremio two seasons ago, and given the Spanish club's financial problems, a fee of £8m may be sufficient.

Jonas, who has a year and a half left on his contract with Valencia, has already scored eight goals in 12 La Liga game this seasons - including a hat trick against Osasuna last weekend.