Sale Sharks centre Mark Jennings failed a late fitness test and has been replaced by Northampton Saints centre Tom Stephenson, with Purdy coming on to the bench.
Purdy has been involved throughout this season’s Under-20s Six Nations, while Tigers colleague Harry Wells starts in England’s back row.
Wales are unbeaten in this season’s Championship while England have lost just once but have a better points difference, meaning this clash in north Wales is winner-takes-all.
The match is a 7.35pm kick-off on Friday at Parc Eirias, Colwyn Bay, and is screened live on S4C.
England Under-20
15 Ollie Devoto (Bath Rugby)
14 Anthony Watson (London Irish)
13 Tom Stephenson (Northampton Saints)
12 Sam Hill (Exeter Chiefs)
11 Jack Nowell (Exeter Chiefs)
10 Henry Slade (Exeter Chiefs)
9 Callum Braley (Bristol Rugby)
1 Luke Cowan-Dickie (Exeter Chiefs)
2 Nathan Morris (London Wasps)
3 Kyle Sinckler (Harlequins)
4 Elliott Stooke (Gloucester Rugby)
5 Dominic Barrow (Leeds Carnegie)
6 Harry Wells (Leicester Tigers)
7 David Sisi (London Irish)
8 Jack Clifford (Harlequins)
Replacements
16 Max Crumpton (Saracens)
17 Danny Hobbs-Awoyemi (Northampton Saints)
18 Danny Herriott (Northampton Saints)
19 Tom Jubb (Saracens)
20 Gus Jones (London Wasps)
21 Alex Day (Northampton Saints)
22 Henry Purdy (Leicester Tigers)
23 Ben Howard (Worcester Warriors)
