Craig Gordon has been doing extra homework on Brendan Rodgers' demands on his goalkeepers in a bid to regain the Celtic No 1 spot.
Gordon lost his place to Dorus de Vries, who worked with Rodgers at Swansea, for big games against Aberdeen, Rangers, Barcelona and then Inverness.
But the goalkeeping spot still seems up for grabs after the Dutchman conceded 11 goals in those four matches before being beaten by Souleymane Coulibaly from more than 40 yards during Celtic's 6-1 win over Kilmarnock on Saturday.
De Vries went off at half-time with a chest injury and Gordon got 45 minutes to show Rodgers what he has learned on his lay-off.