Celtic are yet to make their first signing this summer as Brendan Rodgers takes stock before pushing any buttons in the market. Speculation is rife regarding potential arrivals, and there has been no shortage of links far and wide to players who could improve the Irishman’s squad. Herediano forward Andy Rojas and BK Hacken’s Pontus Dahbo are said to be on the agenda; meanwhile, the hunt for a new stopper at Parkhead continues to take shape. Sparta Prague goalkeeper Peter Vindahl Jensen and Newcastle United’s Martin Dubravka are thought to be among the frontrunners; nevertheless, it looks like …