The offensive tackle from Penn State, selected fifth overall, has missed the first three days of practice at Arizona's training camp in Flagstaff.
"We don't have a deal in place but I felt like we made very good progress today," Cardinals general manager Rod Graves said. "We still have some work to do on a couple of issues but I certainly feel good about the way they progressed today."
Brown's agent, Joel Segal, did not return a message left on his cell phone late Tuesday.
The players immediately ahead of and behind Brown have reached deals.
Defensive end Gaines Adams, the No. 4 pick, agreed to a six-year deal with Tampa Bay reportedly worth up to $46 million, with $18.6 million guaranteed. Defensive back LaRon Landry, the No. 6 pick who also is represented by Segal, agreed Monday to a five-year, $41.5 million contract with Washington, with about $17.5 million guaranteed.
Brown has played mostly at left tackle, but that spot is held by free agent acquisition Mike Gandy. Oliver Ross has worked with the first team at right tackle so far in camp. Ross played for Whisenhunt when the coach was offensive coordinator at Pittsburgh, but lost his starting job with Arizona during last season.
Brown was the second offensive lineman chosen in the draft. Cleveland selected tackle Joe Thomas as the third pick overall. Thomas has signed a six-year deal reportedly worth $42.5 million, with $23 million guaranteed.