METAIRIE, La. -- Rookie cornerback Marshon Lattimore did not return to Monday's practice after walking off with a trainer early in team drills with an unspecified issue.
Coach Sean Payton suggested it might have been a hydration issue -- though he wasn't positive immediately after practice and declined to elaborate on any injury questions. Starting cornerback Delvin Breaux was also absent Monday with an unspecified injury issue.
Lattimore, who was the 11th pick in this year's NFL draft, has shown flashes of his great speed and athleticism throughout summer practice sessions. However, he remains a work-in-progress after having just turned 21 and having spent just one full year as a starter at Ohio State because of hamstring injuries early in his career.
Lattimore lined up with the starting unit Monday when the Saints started their team drills in a nickel defense. The 6-foot, 192-pounder has mostly been working with the second string in base formations throughout training camp. But he will get a chance to unseat third-year pro P.J. Williams as a starter if he shows enough development throughout the preseason.
Breaux should have a lock on the other starting cornerback job if healthy. The physical 6-foot-1, 210-pounder emerged as New Orleans' No. 1 cornerback in his debut season in 2015 after migrating from the Canadian Football League. But injuries derailed his sophomore campaign last year. He was limited to just six games because of a broken fibula in Week 1 and a shoulder injury late in the year.
Williams, veteran Sterling Moore and young backups Ken Crawley, De'Vante Harris and Arthur Maulet are also jockeying for positions on the Saints' cornerback depth chart. Crawley and Moore each had some notable moments with the starting unit in the wake of Monday's injuries.
Another rookie the Saints are counting on in the secondary -- second-round safety Marcus Williams -- had his biggest highlight to date in camp on Monday when he intercepted a pass from backup quarterback Chase Daniel, which was thrown behind receiver Brandon Coleman.
Williams (6-foot-1, 195 pounds) has mostly worked with the second string so far. But he is known as a ball-hawking center fielder, so he could earn a larger role if he continues to make opportunistic plays like that.