Celtic boss Brendan Rodgers will be keen to open his chequebook once the summer transfer window opens for business. Throughout the squad, the Irishman is likely to acquire reinforcements as he looks to build on a successful first season back at Parkhead, where he had led the Bhoys to the Scottish Premiership title. This weekend, there is also the opportunity for Celtic to claim the Scottish Cup before the campaign concludes, before the summer break then kicks in and recruitment chatter gets underway. According to reports, Wolfsburg goalkeeper Koen Casteels has been mooted as a potential high-p…