Most of the nation's elite Division II programs return to the mat this weekend after the short holiday break.     Second-ranked Central Oklahoma, off since Dec. 7, will compete in the Lone Star Duals on Saturday in Dallas.    Third-ranked Nebraska-Omaha, which last wrestled Dec. 8 at the Nebraska-Kearney Open, is hoping a number of its injured wrestlers can return when it plays host to the Glen Brand Open on Saturday.    The Mavericks compete in their final open tournament before they face North Central Conference foes Northern Colorado and South Dakota State in a pair of home dual meets next week.    Ashland (Ohio), which has climbed to No. 4 in the Division II rankings, is slated to wrestle in the Midwest Classic on Friday and Saturday in Indianapolis.    Minnesota State-Mankato, ranked fifth, will wrestle at Division III power Luther (Iowa) College on Saturday.    Minnesota State will then wrestle at No. 1 North Dakota State, the two-time defending national champion, in a key NCC dual on Jan. 12 in Fargo, N.D. That will be the first meet for the Bison since Dec. 15.    Sixth-ranked Pittsburgh-Johnstown will return to action when it competes in the Millersville University Invitational on Saturday.    South Dakota State, which has tumbled five spots to No. 7 in the rankings, wrestles at Southwest State (Minn.) on Saturday. The Jackrabbits were second in the country last season.