Jockey Shane Sellers won two races at Arlington Park Saturday, including the featured Spectacular Bid Stakes with Double Zero Seven, then announced he was ending his comeback bid. Sellers, the 34-year-old jockey who suffered a career threatening injury at Fair Grounds this winter, returned to the races in late August."This is a very emotional moment for me after coming back," Sellers told Arlington's Christine Gabriel over the track's television network. "My knee is just not good. The pain is just too much. I'm going to have to take some time off now. I'm going to go home (to Louisville) and consult with my doctors. I'm just grateful that I was able to come back and get to the winner's circle one more time. It (taking some more time off) is just something I have to do."Sellers continued to say that the respite may be permanent."I just have to go back and regroup," he said. "Maybe it's time to call it quits but I hope not."Sellers' surprise announcement meant that trainer Patrick Biancone might have to find a replacement for City West in Sunday's CAN$1-million Atto Mile at Woodbine. According to the Toronto Sun, late Saturday Biancone was trying to convince Sellers to make the trip.