The New Orleans Saints tried to alleviate some congestion in their crowded backfield this offseason by trading running back Chris Ivory to the New York Jets. But then they went and added a new undrafted free agent Khiry Robinson whose performance is demanding he remain part of the rotation. Robinson (6 feet 220 pounds) has made the most of his limited opportunities over the past four weeks since Mark Ingram went down with a toe injury. Ingram is expected to return to the lineup after the Week 7 bye. But the Saints will likely try to figure out how to keep Robinson in the mix along with Pierre Thomas Darren Sproles and Ingram. Robinson had his most outstanding performance to date in Sunday’s 30-27 loss to the New England Patriots. He gained 53 yards on seven carries all in the second half -- including a terrific 20-yard gain a 16-yard gain and a 3-yard touchdown. In addition to his power-speed combo Robinson has shown great instincts and vision on several nifty cutback runs this season. That was especially true on his 20-yard gain in the fourth quarter against the Patriots when he cut back outside to the right then kept his balance while breaking a leg tackle. Unfortunately on the very next play Robinson committed the ultimate sin for a rookie trying to earn trust. He appeared to fumble the football on a 4-yard gain up the middle. Although a fumble wasn’t called on the field the Patriots may have challenged the ruling if Saints left tackle Charles Brown hadn’t recovered. Robinson also fumbled twice in the fourth preseason game. And when asked Monday if Robinson is earning his trust Saints coach Sean Payton immediately mentioned the fumble. “I think the ball came out on a play” Payton said. “I thought he handled the opportunities outstanding. But the ball security for a young player of understanding how difficult it is in our league is something we will continue to work on.