Trainer Jimmy Jerkens saddles Tricky Zippy (#10, ML 6-1) in Thursday’s ninth race at Saratoga, the 6 1/2-furlong Union Avenue Stakes. Since Jan., 1, 2014, Jerkens is winning at a 26 percent clip in stakes races, for a return on investment of $3.74. Check out the Positive ROI report as part of DRF Plus. Sign up for DRF Plus here.