The Sheffield Wednesday forward is currently out with a hamstring injury.
Forestieri was expected to miss between six and eight weeks after picking up a hamstring injury at the start of December.
And the Argentine forward looks on course to return within that time-frame, although Bullen - who HITC Sport understands will hand over control of Wednesday's first team to Steve Bruce this week - is happy too make him wait.
"Forestieri is closer (than Kieran Lee and Gary Hooper) to coming back," the Owls' caretaker manager told BBC Radio Sheffield. "He's done a fair bit of rehab down in London. He should be back after the weekend, I think. Whether he's ready to go into full training I'm not sure, we'll just have to assess him at that point.
"But he seems to have done a heck of a lot - we've been sent videos every day, the doctor's had an update every day from the physio down in London. He seems to be progressing very well.
"But the last thing we want to do with Fernando is (repeat what happened last time), we brought him back in when he felt he was 100 per cent, he's played a game, he's a played a second game and then it's gone again.
"The worst thing is having to stop-start, especially with the hamstring situation. I felt that at the end of my career that's exactly what hindered me. So I've always been told that if you feel 100 per cent fit then you're still a week away from being ready."
Top scorer in each of his first two seasons at Sheffield Wednesday, Forestieri has only played 24 times throughout the past 18 months due to various ailments.
The 28-year-old was temporarily pursued by police over his failure to attend court last week, although the Owls later clarified that a new date has now been set after neither they nor the player's legal team were made aware of the previous one.