The midfielder - who was born in England, but qualifies for Scotland through his father - has scored 11 goals in 35 appearances for the Championship leaders this season, and could take his first steps on the international scene as Gordon Strachan's side face Northern Ireland and Gibraltar next week.
A 26-man squad has been selected ahead of fixtures against Northern Ireland in a friendly on March 25, before Gibraltar head to Hampden Park in a Euro 2016 qualifier four days later.
Ritchie is joined in the squad by the returning Jordan Rhodes, the Blackburn Rovers striker replacing the injured Chris Martin as one of five forwards in Strachan's squad.
There is also a recall for Hull City's Allan McGregor, the 33-year-old regaining his place from Matt Gilks after missing out on the last squad with a shoulder injury.
