Tom Coughlin said last week one of his priorities this offseason is to rebuild the Giants' run defense. It appears that project will start in the middle of the defensive line. The Giants have been nosing around several free-agent defensive tackles over the last few days, including Tennessee’s Sen’Derrick Marks, according to an NFL source. The 26-year-old Marks was a second-round pick out of Auburn in 2009 and emerged as the Tennessee Titans' best run-stuffing lineman over the last few seasons. Marks could become a bit pricey, though. According to The Tennessean, the 6-2, 294-pounder is being pursued by five teams, including the Giants and the Titans, who would like him back if the price is right.