GREEN BAY – With a tight roster, the Green Bay Packers were able to sign only nine undrafted free agents on Saturday. One of those players is tight end R.J. Maryland, according to a source. Maryland had four productive seasons at SMU, where he finished his career with 113 receptions for 1,493 yards and 19 touchdowns. Maryland knows the game. His father is Russell Maryland, who won three Super Bowls and was selected to one Pro Bowl with the Dallas Cowboys and wrapped up his career with the Packers in 2000. “He’s been great throughout this pre-draft process,” Maryland told NFL Draft On SI’s Justin Melo . “He’s being a dad (laughs). He’s been cooking for me and making sure I’m eating right. He’s just my dad, you know? He’s been awesome.” Why he’ll make it: At 6-foot-4 1/8 and 236 pounds, Maryland ran his 40 in 4.51 seconds. He’s going to have to show he can block in order to make the roster, but the height and speed makes him a tantalizing prospect. “I know I’m going to be a productive NFL player,” he said.…