Marquis has not scored in his last eight appearances, last netting in Feburary’s 3-0 win over Southend United.
But Byrne insists his contribution to the team during that run has been as important as goals and that the striker is unfazed by his own personal drought.
“If you know John as well as I do you know he doesn’t suffer from a lack of confidence,” Byrne said.
“He’s a terrific character and he’s fabulous for this football club.
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“He’s made a massive contribution this year.
“People look towards goals as John does but people don’t see everything else he does.
“There absolutely has been no dip in form with him.
“If people are going to judge him on goals, and they will do with a goalscorer, the number of goals he has to date is quite high in the league already.
“He’s fully focused on making this team successful this year.”
Marquis – this week nominated for the League One Player of the Year Award by the EFL – turned in an excellent performance in Tuesday’s 4-1 win over Bristol City, operating as a lone forward with support from Kieran Sadlier, James Coppinger and Mallik Wilks.
All three of those players found scored in the win but Marquis' work helped create space and opportunities for them to strike.
It is a role Marquis – who has netted 22 times this term – seems likely to fulfil again this weekend as Rovers welcome Walsall and boss Grant McCann is confident the goals will come.
“John was unbelievable on Tuesday night,” McCann said.
“The amount of work he put in was second to none and I was just gutted he didn’t get the goal he deserved.
“But there's no problem with that. He’ll score plenty of goals from now until the end of the season.”