The former MK Dons hitman suffered a hamstring strain in training last week and was forced to pull out of the Buddies' trip to Tynecastle where they lost to Hearts.
But the 27-year-old has come through a light training session and is bidding to convince Saints gaffer Danny Lennon that he is ready to face the resurgent Dens Park men.
The five-goal hitman said: "The injury happened in training last week and it was a big frustration to sit out the trip to Tynecastle.
"But I am looking to take part in a full training session tomorrow and fingers crossed I will come through that one unscathed and then be able to build towards Saturday's game with Dundee, which is massive game for both sides.
"I am desperate to be in there giving it my all."
With Saturday's setback at Tynecastle representing Saints' sixth in succession, Guy has no doubt that the Dundee game is a massive opportunity for the Paisley side to end their slide into the relegation zone.
He said: "Obviously Dundee have picked up in recent weeks while we have not been getting the results we would have liked.
"The gap between us and them is down to just one point.
"But we have got to look at this game as a huge opportunity to knock them back a bit, restore the gap and put an end to our run of losses.
"The great thing for us is that we have home advantage and with the importance of this game I am sure we will get a big home crowd out to get behind us.
"To be fair the fans have been fantastic and stayed right behind the team and I think they can see we have not been getting any breaks.
"If you look at Hearts' winner on Saturday then it was a freak deflection that could have gone anywhere.
"Against Dundee, though, we need to make our own luck."