The defensive midfielder, a free agent since parting ways with Dunfermline in January, was on trial at Plainmoor in the spring. But Ling is keen to stress the 33-year-old Scot would not be brought in to fill a potential gap should attacked-minded midfielder Eunan O'Kane complete his move to Crawley.
"I'm chasing Craig Easton but I don't see him as a replacement for Eunan," Ling told the club's official website. "I'm looking for two centre midfielders if Eunan goes, and hopefully one will be Craig.
"I see him more as a back-up to Damon Lathrope or a fighter with Damon. I always felt last year that when Damon was missing it made us worse because I had nobody capable of filling the role naturally.
"Craig can do that, as well as playing the Lee Mansell or Eunan O'Kane role, but he would be here to bolster the midfield unit and not replace."
Meanwhile, Ling has revealed transfer-listed Chris McPhee has attracted a handful of enquiries from clubs and is likely to go out on loan this summer.