The Netherlands international needs to apply himself in a better way, according to the recently appointed Black Cats boss
Lens joined the Premier League strugglers from Dynamo Kiev in July, but has failed to make a significant impact, firstly under previous boss Dick Advocaat and now Sam Allardyce.
The Netherlands international has been dropped to the bench in recent weeks and Allardyce says he must up his work-rate if he wants to get another opportunity in the starting XI.
He told the Sunderland Echo: "I think what Jeremain has to do overall, like they all have to do, is to lift his level up in terms of work-rate.
"There is no doubt at this level of football the size of the work-rate needed.
"With each position, I have the levels of an elite performer and an average performer for a Premier League player. It's easy for me to monitor.
