The 23-year-old fly-half is on course to be fit for Harlequins’ Champions Cup trip to Racing 92 on Sunday, January 15.
Smith suffered an ankle injury in England’s 27-13 defeat by South Africa on December 2, bringing his fruitful 2022 to a premature end.
Steve Borthwick is likely to name England’s Six Nations squad on Monday, January 16, leaving Smith with just enough time to prove his match fitness with Quins.
“Marcus trained fully on Wednesday, and he was on the tackle mat with me at the end of training, and that’s fantastic,” Harlequins head coach Tabai Matson told Standard Sport.
“He’s not available this week, but he’s days not weeks away now from being available. He was scheduled to be available in Europe, and he’s on track for that, so that’s great.”
Sale’s George Ford stands a fine chance of an England recall in new head coach Borthwick’s first Test squad, with the Six Nations starting with Scotland calling at Twickenham on Saturday, February 4.
Smith will hope to force his way into an inside back contingent bound to include captain Owen Farrell, with Exeter’s Henry Slade also expected to feature in the centres.
Quins boss Matson believes Smith will hit back from his injury and quickly show himself improved again, even from the levels he had hit before that ankle blow.
Smith will miss Harlequins’ Premiership clash with Sale at The Stoop on Sunday, but has still managed to impact the Twickenham club’s preparations for hosting the league’s second-placed side.
“I’m really excited about seeing Marcus get even better again,” said Matson. “The way he trained on Wednesday; lordy, lordy. He was outstanding helping the first team to prepare for Sunday’s game against Sale.
“I think a mental break will have done him good as well. He’s been so durable, so consistent, and go, go, go. But you have to hope there’s a silver lining from something like this.
“Sometimes you need a little sit back to recalibrate, and he’s grown other skills, worked on other parts of his body, and that’s what having injury does.
“He’s a lead by example guy, but what he’s had to do now is lead off the field and be more influential, not by saying ‘follow me’, but actually by guiding other people, and that’s great for his skill-set.
“He’s 100 per cent the whole time, so he’s had to put on the breaks, stick his feet up and let his body heal, and that’s not a bad thing.”
Third-placed Harlequins will be itching to get back to winning ways on Sunday after consecutive Premiership losses, the 15-12 home reverse to Bristol and the comprehensive 46-17 defeat at Northampton.
“There have been some pretty harsh chats around the way we’re preparing, our standards, this week,” said Matson. “We’ve lost two in a row and if you’re serious about a top-four finish then you’ve got to stop the rot.
“Feeling frustrated around poor performance is important, but that’s cured by positive action. Unfortunately sometimes it can take a poor defeat for people to switch on just that bit more.
“We’ve got a red-hot Sale coming in, and if we don’t get that right it will happen again.”