Rory McIlroy has advised Scottie Scheffler to change his putter to a “mallet” from a blade to try and fix his issues on the green – but he’s secretly glad the world No 1 is going through some problems. There’s been no better ball striker on the PGA Tour than Scheffler over the past 12 months. He’s far ahead at the top of the PGA Tour rankings and hasn’t finished outside the top-17 at any of his previous eight tournaments. That kind of consistency makes Scheffler one of the most dangerous opponents for anyone on tour hoping to clinch a trophy. But the only reason Scheffler hasn’t won more in th…