Cleary also admitted the club has yet to enter discussions with the 2005 premiership winner on possibly extending a contract that expires at the end of the season.
He said Marshall had regained confidence following a challenging period that began with his messy split from the Tigers in 2013 and involved stints in rugby, the Dragons and Broncos. Cleary said it was difficult to predict how long Marshall could play on for.
"He's also at that time in his career, that age, where it's hard to forecast," he said. "As long as you're feeling good about training, want to turn up each day and make the sacrifices you need to play well on the weekends, there's no reason why he couldn't keep going. But at the end of the day, it's going to be up to Benji."
With Josh Reynolds this week ruled out for up to a month with a shoulder injury, Tigers officials are set to get an extended look at Marshall in the halves.
"We weren't sure how that was going to pan out, but it's always going to be nice to have a guy like Benji. The way it's turned out, it's going well at the moment," Cleary said.
- AAP