Even though injured cornerbacks Jabari Greer and Patrick Robinson were unavailable, Johnny Patrick lined up at his customary nickel spot with the first-team Saints defense on Tuesday morning.

Greer’s and Robinson’s absences are expected to be temporary. Patrick, New Orleans’ No. 3 cornerback, needs all the reps he can get at nickel if he wants to be a permanent replacement for the departed Tracy Porter in the secondary rotation.

“Nickel’s a hard position to play,” Patrick said. “It’s a lot of thinking. You have to know a lot. In addition to corner, you have to be a linebacker or a safety. I’ve improved mentally a lot.”

Physically, he still has plenty to prove. He tore an MCL in the Saints’ first preseason game of 2011, and the injury hampered him for most of the year. Although he returned to practice with a knee brace by the end of the preseason, he said it was much longer before he felt right.

He finally played in the last three games, making six tackles.

When the Saints did not re-sign Porter (Denver) or cornerback Leigh Torrance (Washington) in the offseason, Patrick knew he had a huge opportunity.

“I feel like the coaches had enough faith and belief in me to let Tracy Porter and Leigh Torrance go,” he said. “Right now, they are focusing on me to be that No. 1 nickel spot, so I’m taking full advantage of it.”

Patrick has not made many big plays in the first week of training camp, but he also has not been burned much.

“I don’t feel like I’m where I want to be right now,” he said. “I feel like I have a lot of learning to do. That’s why we are in camp right now.”

Follow Saints reporter Guerry Smith on twitter @CBSSportsNFLNO.