Celtic take on St Johnstone in the Scottish Premiership on Saturday in a must-win affair for the Bhoys. There’s no more room for error in the title race and, having lost to Hearts in their last league match, it’s critical for Brendan Rodgers’ side to pick up all three points. Doing so would put Celtic back at the top of the table overnight and subsequently put pressure on Rangers, who travel away to Dundee on Sunday. Celtic have several injury concerns to contend with. It was revealed on Friday that Liam Scales is the latest to sit on the sidelines after picking up a knock, joining Callum McGr…