Eddie Howe was right when he said it will be very costly for Newcastle United to replace Callum Wilson. The Magpies are weighing up who to bring in this summer, with Newcastle even more keen to sign a striker following news of Callum Wilson’s injury. The 32-year-old is a doubt for the first Premier League game of the season against Southampton due to a back problem, which has only enhanced the argument that Paul Mitchell should sell Wilson as he enters the final year of his contract. But he will need to be replaced, and that will be difficult. Earlier this year, Eddie Howe warned Newcastle tha…