Celtic’s summer transfer window hasn’t kicked into high gear yet. Or any gear, really. Yet to make a single signing, some fans are starting to air concerns about another underwhelming window. It’s too soon for widespread criticism or panic with just under two months to go until the deadline, but questions will be asked until Celtic start getting bodies in the door. And the first phase of Celtic’s window arrives much sooner than late August. Brendan Rodgers has noted he hopes to see signings in the door before the upcoming USA tour, giving the Celtic board just 10 days to deliver a deal or two….