The midfielder gets his opportunity after impressing in scratch matches over the last couple of weeks.
The former Sandringham Dragons captain was taken with Pick 52 in last year’s draft.
Byrnes becomes the second debutant for the Saints this season, joining emerging key forward Max King.
The Saints and Crows will announce squads of 26 today at 6.20pm (all times AEST), with final teams to be known at 4.30pm Saturday.
The Monday night clash at Adelaide Oval will close out the round at 7.40pm.