The Australian full-back has been out of action since rupturing his anterior cruciate ligament against Halifax last September.
Such was his influence, Quinlan was the club’s player of the year and players’ player of the year and his attacking quality, in particular, has been missed at times this season.
Given how complex the injury was, Rovers did initially fear he would miss all of the 2019 campaign.
However, June was then set as his likely comeback and he has been in full training for the last five weeks and is set to feature against Warrington Wolves on Saturday.
It is a timely boost for the Robins who have fallen to joint-bottom and have just one league win in their last seven outings.
Smith, who took charge for the first time in Sunday’s 19-18 home loss against Wigan Warriors, said: “He (Quinlan) is likely to be back this week.
“I haven’t quite finalised the team as yet but I reckon he’s 85-90 per cent.
“He’s still got a couple of little hoops he’s got to jump through. I’ll be surprised if he doesn’t play this week, which is good for us.”
Rovers will not expect too much too soon from the 26-year-old and Smith said: “He’s a good little player and will try his best.
“That’s the only expectation I have on him or any of them.
“It’ll be good to have him back and a calibre of player like him back this week.”
However, Rovers have suffered a setback with Danny Addy, the versatile Scotland international, facing up to six weeks out with the hamstring problem that saw him limp off against Wigan.
“It isn’t ideal,” admitted Smith, who admitted Danny McGuire will also be absent again after missing the Wigan game due to a calf injury suffered in training.
“It’s disappointing for him, particularly when a new coach comes in.
“They’re all keen to show you what they can do and he was keen to get a bit of an opportunity at hooker and show he can play there.
“He’s such a versatile player who has bounced around so many positions and I think he was so keen to show he can be good at that position as well as so many others.
“He finds himself on the injury list but he’ll be back in a few weeks’ time and get a chance to prove himself.
“Fortunately I’ve got a few options there with Tommy Lee who’s fit now, Shaun Lunt, George Lawler and Chris Atkin.
“There’s some specialists there and some versatile players who can do a job there. “We’ve got a few options on what to do. So we’re covered but I’m just disappointed for Danny really.”
On McGuire, Smith added: “He won’t be ready but he’s better than I thought and could make the derby.
“He certainly won’t make London (week Thursday) but maybe the week after. “Initially we didn’t think he’d be back that quick but he does everything right and is a good pro’.”
Australian centre Kane Linnett will miss Saturday’s game, too, after being stretchered off with a neck/head injury against Wigan.
Smith, who replaced the sacked Tim Sheens last week, added: “Kane came in today for the first time but he’s still got little bits of concussion ailment.
“He wouldn’t have been featuring this week anyway with the turnaround.
“We’ll see how he settles down over the next few days. The main thing is he’s OK and it was good to see him today.”