The Owls skipper, who sustained the injury in training was ruled out for the Stockport game and has not featured since.
It is the first time he has missed any action at all this season through injury - although he did not play against Oldham in August because of family issues.
When asked about the severity of his injury, the former Coventry and Southampton midfielder was hopeful a quick resolution can be found before an operation is needed.
He exclusively told Footymad: "Your guess is as good as mine to when I will return to fitness – it could be two weeks, four weeks or even six months it is that up in the air at the moment but I’m hopefully going to stick to the first one.
"I have a problem with the top of my hamstring with the tendon that attaches to the bone. It’s out of shape at the moment and badly deformed and hopefully the people I am working with away from the club can fix it otherwise I may have to go under the knife, something I don't want to do but I just want to play football and get fit again."
But looking on from the sidelines, Marsden is more than impressed about what he is currently seeing with the squad and believes if the mentality is right, Wednesday will be successful.
He added: "Since Paul came in we have had more opportunities to win games but sometimes not really taken our chances and that really has been the story of our season.
"But personally I don’t think we have a problem in this league as it all boils down to concentration and making sure we do things right, and if we do that we will do really, really well."
More with Chris tomorrow as he talks about the progress made by Wednesday's young players.