The Dallas Cowboys are planning to split with eight-time Pro Bowl left tackle Tyron Smith, making the veteran a free agent when the new league year begins March 13, NFL Network reported Saturday.Last month, The Dallas Morning News reported that Smith didn’t plan to retire and had hoped to return for a 14th season with the Cowboys.The protector of Dak Prescott’s blind side, the 33-year-old Smith likely should have several suitors in free agency.