Roberts has slipped well down the pecking order with Nikola Kalinic and Mame Biram Diouf being preferred up front by Sam Allardyce.
But now the 32 year old is frustrated and wants to know why he is being left out of the side when he was the second highest scorer at the club last season.
Roberts maintains that he is still fighting hard to earn a chance and hopes the situation will turn around soon.
Speaking to the Daily Mirror he said: "I am still the same player that finished second in the club's goalscoring charts last season.
"There's not much I can do apart from keeping myself as fit as I can.
"If I'm called upon I will do the best I can.
"If not, maybe we will look to do something in January or at the end of the season."