Freshman receiver Travon Patterson was Warren's host, and the player he used to match up against in practice with the Jackrabbits did a worthy job.
"I spent a lot of time with him and Al (Alfred Rowe) and Vincent (Joseph), all those guys," said Warren. "They were trying to get me to commit, but they know what its like."
Warren said he was pretty familiar with the USC campus, so this trip allowed him to take a closer look at things that he wouldn't get to see on a normal visit.
"I pretty much know where everything is exactly, so this time I really got to hear about the academics and how they help you out with your work," said Warren.
While the Trojans have been one of, if not the favorite throughout his recruitment, Warren said he went into the trip as open-minded as he could be.
"I'm going to look at each school open-mindedly," said Warren. "I went to USC open-mindedly and just was checking out the atmosphere with the players and the coaches. I spent a lot of time with Coach Seto, Coach Carroll and I talked a lot and I spent time with Coach Holt, the defensive coordinator. They just told me whenever I'm ready to commit, it's open arms."
Warren was able to watch USC practice in preparation for the Rose Bowl and he used that time to focus on the defensive backs.
"Seeing how they are going in to practice, I know it's always a high tempo and just like a game. So I got a chance to see the things that they do in getting ready for practice and all of the preparation for it. I really was focusing on the that and how the DB's react to the coaches and the energy from the guys."
Warren has already visited Arizona, Michigan and California officially and will visit UCLA next month. He said he's still targeting Signing Day to make his announcement.
The next two weeks, he plans to take off from recruiting while getting ready for the U.S. Army All-American Game.
"I'm going to go get ready, lift a little bit and raise my game," said Warren. "I'm real anxious because I'll be going up against the best players in the country for this."