They were signed on Wednesday to one-year, two-way contracts. Each deal is for $600,000 at the NHL level. At the AHL level, Exelby's is worth $130,000 and MacDermid's $70,000.
Exelby, 30, played 75 games last year with Detroit's AHL team in Grand Rapids and had seven goals and 14 assists with 177 penalty minutes. He's played 408 NHL games with Atlanta and Toronto.
MacDermid, 22, played five games with Boston last season and 69 with its AHL team in Providence where he had four goals, 12 assists and 121 penalty minutes.