Preissing suffered a lower-body injury in the Senators' 4-1 victory Wednesday night over the Toronto Maple Leafs.
Malec, who cleared waivers last Tuesday and was assigned to the Binghamton Senators of the American Hockey League, had six penalty minutes in four pre-season games.
Preissing, who had 43 points in 74 games for the San Jose Sharks last season, was acquired by Ottawa in the Martin Havlat trade with Chicago last July.
Malec recorded one goal, 28 assists and 118 penalty minutes with Binghamton last season. He also had two penalty minutes in two games with Ottawa.