Clarke has been forced into making some huge calls in defence due to injuries to Kieran Tierney and Scott McKenna, with Hibs defender Ryan Porteous selected for his debut.
The 23-year-old will likely be part of a central defence alongside Jack Hendry, with Aaron Hickey and Greg Taylor playing as wing-backs.
In midfield, Ryan Jack comes in to replace Scott McTominay, who is suspended for the match in Poland following his yellow card against Republic of Ireland on Saturday, while Kenny McLean replaces Stuart Armstrong.
Ryan Fraser is preferred to Ryan Christie out wide in what appears to be a 4-5-1 formation.
In attack, Southampton’s Che Adams is recalled to the starting XI in place of Lyndon Dykes, who drops to the bench.
Midfielder John McGinn captains the team in the absence of regular skipper Andy Robertson.
Scotland team to play Ukraine: Gordon; Hickey, Porteous, Hendry, Taylor; McLean, McGregor, Jack, McGinn, Fraser; Adams. Subs: Kelly, McCrorie, Gallagher, Kingsley, Dykes, Christie, Gilmour, McKay, Ralston, Armstrong, Doig