Roberts, 53, wants to see more from the Togo forward as Spurs chase a top-four spot and Champions League qualification.
He said: “Adebayor has got to do more. He’s a striker and he has to score 20 goals a season.
“If you’re going to qualify for the Champions League and you’re going to try and win trophies then your strikers have to be scoring goals.
“He’s been disappointing this year. He’s let the supporters down and he’s let the manager down.”