Not all of Jason Garrett’s time these days is spent hanging out with Tony Romo at college basketball games. Organized team activities begin in three weeks. The draft comes 21/2 weeks later. Action is about to heat up at Valley Ranch. The Cowboys head coach talks about the players the club has signed this off-season, his new emphasis on defense, his thoughts on a couple of young defensive players and the addition of Scott Linehan to call plays on offense. On adding defensive linemen Terrell McClain, Jeremy Mincey and Henry Melton in free agency: “We feel like [McClain] is an interior player who can have an impact on our team,” Garrett said. “We’re excited about just really seeing him. Is he truly a nose, is he a potential under tackle, a three-technique? “Mincey is just a really solid football player. We see him as a defensive end candidate. He plays hard, he plays the right way and has done that a number of years.” Garrett spoke of the impact Melton had at defensive tackle in Chicago and how the snaps he spent as a Grapevine High School and University of Texas running back come into play. “You see some of those running back traits in terms of quickness, explosiveness, change of direction,’’ Garrett said. “He was hurt last year and only played in three games. He’s coming off an ACL, but he played very well for Rod Marinelli a couple of years ago and I feel like we can get him to that place.’’ Would Garrett consider inserting Melton as a fullback near the goal line? “He was very quick to tell me that he was a running back, not a fullback, in high school and college,” Garrett said. “That guy Jamaal Charles kinda got in his way down there at Texas. “It was a long discussion and a long explanation.”