He's joined by fellow Warriors James Eddie and Iain Kennedy. John Beattie been forced out of the tournament with an elbow injury.
The selectors have made seven changes, two of which are positional, to the team which lost to England last Saturday in their final pool game.
Colin Goudie comes in at full-back for James King while Iain Kennedy moves from inside centre to left wing making way for Chris Dunlop. Kyle Traynor starts at hooker for Sean Crombie, Scott Newlands takes over on the blindside from Alan MacDonald who moves to the openside instead of Ross Rennie and John Barclay replaces John Beattie.
Coach, Iain Paxtoon said: "Georgia have a big powerful set of forwards and so we've picked a team to play accordingly. Although they haven't picked up any points in this tournament, they only just lost to our U19s last year.
"We put a lot of effort into our group games so we're still disappointed to be contesting for the bottom places but we just have to get on with it and finish the tournament with two good wins."
Scotland play Georgia in the first round of the play-offs to determine ninth to 12th place, after losing two of their three pool matches. They were beaten by Australia 18-14 in the 85th minute of their opening game, before beating Italy 26-10 and losing to England 31-12.
Scotland U21 team to play Georgia in the IRB U21 World Championship
at the Complexe du Mas in Issoire, France on Wednesday 21 June (kick-off 5.00pm local time, 4.00pm BST)
15 Colin Goudie (Stewart's Melville FP)
14 Cameron Johnston (Newcastle Falcons) *
13 Ben Cairns (Edinburgh Gunners and Currie) *
12 Chris Dunlop (Durham University)
11 Iain Kennedy (Glasgow Warriors and Glasgow Hawks)
10 David Blair (Sale Sharks) (CAPTAIN)
9 Greig Laidlaw (Jed-Forest)
1 Ryan Grant (The Army)
2 Kyle Traynor (Edinburgh Gunners and Boroughmuir) **
3 David Young (Leicester Tigers)
4 James Eddie (Glasgow Warriors and Ayr)
5 Ian Nimmo (Leicester Tigers)
6 Scott Newlands (Heriot's) **
8 John Barclay (Glasgow Warriors) *
7 Alan MacDonald (Edinburgh Gunners) *
Substitutes: to be confirmed
* indicates member of Scottish Institute of Sport
** indicates member of an area Institute of Sport
Scotland's fixtures and results:
Friday 9 June Australia 18-14 Scotland Stade Darragon, Vichy
Tuesday 13 June Italy 10-26 Scotland Stade Darragon, Vichy
Saturday 17 June England 31-12 Scotland Stade Emile Pons, Riom
Wed 21 June Scotland v Georgia Complexe du Mas, Issoire, kick-off 5.00pm (4.00pm BST)
Sunday 25 June finals for overall places tbc