Paul Merson has been speaking about Newcastle and Luton this weekend and believes Kieran Trippier’s form is a big worry. Trippier has been in a bit of a struggle lately. He made a couple of glaring errors against Tottenham in the 4-1 loss, while he made a big mistake to allow Chelsea back into things in midweek. All in all, it’s been so unlike Trippier, who we’ve seen be consistent for England and the Toon. For Newcastle, Trippier’s poor run coincides with their own run of bad form. They’ve lost three from five in all competitions now. And Merson, speaking about the weekend’s fixtures, believe…