The striker sat out the draw with Poland due to a hamstring issue with club side Queens Park Rangers not keen for him to play unless he's fit.
Dykes looks like he will be involved in the game in Vienna after coming through training sessions with the national team.
"We discussed the issue before the camp and we were guided by QPR,” Clarke said.
“They allowed Lyndon to come up and join us to watch the Poland game and he’s done a couple of training sessions since and is good to go.”
Aaron Hickey earned his first cap in the draw with Poland and there could be debuts for Craig Halkett and Ross Stewart as Clarke plans to make changes for Tuesday night’s match.
Back-up goalkeepers Zander Clark and Liam Kelly are also still searching for their first cap.
Clarke said: “Looking at the bigger picture and in terms of fairness to the players in the squad more than anything – taking the club issues – it’s a game I’ll probably rotate more than I usually would for the second game of an international break.
“It’s not too bad with the game being on a Tuesday night as they can recover Wednesday and Thursday, train Friday and be ready to go for the weekend - injuries permitting, of course.
“It doesn’t have much riding on it except you’re playing for your country and want to win and we want to continue the run we’re on.”