The 34-year-old Juventus forward was recalled by Portugal coach Fernando Santos for games at home to Ukraine and Serbia, having not played for his country since the 2018 World Cup.
Ronaldo was rested for the last six Portugal games while he settled at his new club following his departure from Real Madrid last July.
The reigning European champions, who are through to the UEFA Nations League final in June, kick off their Group B campaign in Lisbon on Friday against Ukraine before facing Serbia on March 25.
“Cristiano adds quality to any team. It’s a pleasure to play with him and he’s very important for us,” Portugal defender Joao Cancelo, Ronaldo’s team-mate at Juventus, told reporters on Tuesday.