Former Patriots Chad Brown, a free agent who will turn 37 in July, visited Gillette Stadium on Wednesday, agent Peter Schaffer confirmed. Schaffer added that in terms of a signing, ?nothing?s imminent.? The Pats are already five-deep in starting-caliber linebackers, with Tedy Bruschi, Rosevelt Colvin, Junior Seau, Adalius Thomas and Mike Vrabel in the fold. But more depth would be useful, given their 30-something ages and the physical demands of the team?s gap-control system.