With manager Sam Allardyce preferring to play with one up front the 32-year-old has had to battle for a place with £6million signing Nikola Kalinic and on-loan Chelsea forward Franco di Santo.
And despite an impressie strike in Saturday's 3-2 defeat by Everton Roberts knows his chances will remain limited.
"We all get frustrated if we don't play. Me as much as anyone else," he said. "I have been playing football a long time and am used to playing.
"I understand the game is changing, with squads, rotations and stuff but everyone wants to play and there are 30 players on the training field saying the same thing.
"My whole time has been frustrating here, in that I haven't played as much as I would have wanted. But my starts to goals ratio isn't bad and I will keep plugging away and for as long as I am here, I will keep doing what I can."