Thinking back to when he arrived at the Keepmoat in June last year, there were indeed a few question marks about the signing.
Seven loan moves from boyhood club Millwall. Thirty goals in 160 senior appearances, more than a third of which came off the bench.
What were Rovers getting? The answer he has delivered over the past six months has been emphatic.
The 24-year-old sits on 17 goals, all of which have come in the league, with 18 games of the season remaining. He has scored six goals in his last four games.
But arguably as important for Rovers has been a tireless and dogged work ethic that causes nightmares for opposition players and sets a standard for team mates.
Marquis’ journey to this point has been long and winding. A tale of frustration, and desperation to just be handed a real chance to impress.
After being given the chance at Rovers and delivering the goods, Marquis insists he would not the player he is today without all that has come before in his career.
But he is, of course, grateful for Darren Ferguson’s continued show of faith.
“All the time you are involved in something you’re learning, learning how to manage yourself, your emotions being high or low, not scoring for a few games or being in and out of the team,” he told the Free Press.
“In fairness I don’t think I’ve had the consistency in my career before.
“But this season every game bar the one I was suspended for I’ve started and I think I’ve played a full game in the league every time, I can’t remember being substituted.
“That consistency is something I’ve been looking for for a while.
“It doesn’t mean you’re starting every week, it’s not a given, and that’s how it should be.
“But if your performances merit staying in the team it’s good and it gives you confidence.
“As a striker you might have a bad game or two.
“But if you’ve got a manager like we do who has faith in you and knows what you bring to the team whether it’s goals or other things that will help, it’s great to have that.
“I think the goals and the good performances come back around.
“We’re all good players, especially in this division.”
Given the lack of consistency he experienced prior to joining Rovers, Marquis knows full well that a run in a side can end at any time.
Boss Ferguson has demonstrated his ability to alter the structure of his attacking line-up while Liam Mandeville has certainly ramped up the pressure on Marquis and Andy Williams with his own impressive scoring rate this term.
While always wary a spell out of the side could come, he remains confident in what he can bring to the team, with or without goals.
“It definitely keeps you on your toes,” Marquis said.
“Before this month I was on a five game drought and people were saying I’d maybe get 15 for the season, it’ll be okay but maybe I should have a rest out of the team.
“It’s how it is for a striker. You can’t score every game.
“But as long as you’re affecting the team, especially a winning team, it helps me to be playing in it.”
The prospect of Marquis becoming Rovers’ first 20-goal striker in decades is a very real one after he moved onto 17 with a brace in the win over Yeovil Town last week.
So what is the target for the Londoner?
“I didn’t have a target when I started the season to be honest,” he said.
“My target was just to have a run in the team and play as much as I can.
“I’ve been given that opportunity and hopefully now, with 18 games left, I’ll be looking to add to the 17.
“But just as long we’re promoted at the end of the season, that’s all I’m concerned about.”