Viljami Sinisalo became Celtic’s first signing of the summer earlier this week and could be in line to make his debut against DC United this weekend. The 22-year-old arrived from Aston Villa for a fee in the region of £1 million, providing a competent number two to Kasper Schmeichel between the sticks at Parkhead. Capped three times by Finland at international level, Sinisalo gained valuable experience on loan at Exeter City last term, keeping 14 clean sheets in 50 appearances across all competitions [Transfermarkt]. Brendan Rodgers has finally found permanence in a problem position amid Joe H…