Celtic boss Brendan Rodgers has made an intriguing observation regarding potential transfer activity at Parkhead this summer. Conceivably, movement in both directions will be expected as a shake-up occurs. Following his fairytale ending, Joe Hart has retired from football, leaving a void that must be filled between the sticks. Hyeongyu Oh, Benjamin Siegrist, Yuki Kobayashi, Sead Haksabanovic and Gustaf Lagerbielke are among those who could also leave the club, freeing up space for prospective incomings under Rodgers. Supporters are patiently waiting on updates surrounding loanees Adam Idah and…