Meanwhile, former captain Easton Wood has also suffered a hamstring injury, although it is less severe than Jong's.
"Unfortunately from training today, Lin has suffered a high-grade hamstring injury," Bulldogs medical services manager Chris Bell said.
"It was during our match simulation session and he pulled up after accelerating.
"We're going to work through a process with Lin over the coming days to determine the extent of his injury and his return to play plan."
Premiership skipper Wood, who stepped down from the top job in December, is likely to be kept out of the first Marsh Community Series game but should be available for selection for the second week against Port Adelaide.
Tom Liberatore, who recently welcomed son Oscar into the world with his partner Malia, has taken the next step in his recovery from a knee injury, with the midfielder building up his match fitness.
Taylor Duryea (groin) and Riley Garcia (knee) have been building up their running, but are still a way off playing.
Photo: AFL Photos Caption: Easton Wood will miss a couple of weeks but is expected back for the second pre-season game