Rodwell missed a large portion of the 2015/15 campaign through injury and Advocaat admits that until the midfielder stays off the treatment table, he will continue to struggle.
As a result, the 67-year-old boss has warned Rodwell that his career could be heading in the wrong direction, but hopes that he improves considerably next term.
“I had a conversation with him,” Advocaat said. “I think Jack is still a very promising player for this club. He’s only 24 years old, and I still believe in him with the way he can play.
“He can play left, right or central midfield, and in the holding role. But he cannot go on the way he is now, because you can’t count on him. Maybe he trains three days, but then it’s not possible for him to play at the weekend. We have to find how to stop him going on this way.”
Rodwell has had a disappointing first season at the Stadium of Light after joining from Manchester City.
The central midfielder was expected to be one of the best buys in the Premier League when he was signed in the summer, but he has failed to live up to expectations.
Rodwell has made just 26 appearances this season, with the England international having to miss sizeable chunks of the campaign as he nursed his way through niggling knocks.
That has clearly impacted on his consistency and it will be important that the former Everton man shows signs of progression next season if he wants his move to Sunderland to be a success.