Special-teams player Blake Costanzo, who was a Pro Bowl alternate with the 49ers in 2011, will not re-sign with the 49ers, a source told CSNBayArea.com on Tuesday.Costanzo has offers from two teams, according to the source, and neither is from the 49ers. (The Sacramento Bee first reported that the 49ers did not make an offer.)Costanzo, a popular player within the 49ers' locker room, epitomized coach Jim Harbaugh's blue-collar mentality with his play on special teams last season. He ranked second on the team with 17 special-teams tackles.The 49ers might be looking for special-teams players who have more value as backups on defense. The 49ers on Tuesday re-signed backup inside linebacker Tavares Gooden, who also is a core special-teams player.