Hester wore No. 4 in college at Miami. He was allowed to wear No. 23 with the Bears after starting his career as a defensive back. There was some talk that he might have to give up the number once he became a primary receiver, but Hester was allowed to keep it.
NFL rules allow receivers to wear the Nos. 10-19 and 80-89, so Hester is compliant with his new number.
In terms of the other newcomers signed in free agency, all four will wear different numbers: nose tackle Paul Soliai (from No. 96 to No. 97), defensive end Tyson Jackson (from No. 94 to No. 99), offensive guard Jon Asamoah (from No. 73 to No. 75), and cornerback/returner Javier Arenas (from No. 35 to No. 28).