The 28-year-old right wing has been sidelined since the diagnosis on Aug. 13 of the pulmonary embolism, a sudden blockage of an artery in the lung, usually caused by one or more blood clots.
The Rangers said Tuesday that extensive testing showed Ortmeyer has fully recovered from the ailment.
Ortmeyer signed a one-year deal during the summer worth just more than US$550,000 and was expected to resume his role as a key member of the Rangers' checking line. He became a restricted free agent after last season, when he led New York forwards with 75 blocked shots - the seventh-highest total at the position in the NHL.
Ortmeyer had five goals and two assists during the regular season and played in all but four of the team's 82 games. He was one of four Rangers to score a goal against the New Jersey Devils in the playoffs, when New York was swept 4-0 in the first round.
In 136 NHL games over three seasons, the native of Omaha, Neb., has seven goals and six assists.
Ortmeyer, who wasn't drafted, originally signed with the Rangers in May 2003 following a four-year college career at Michigan. He had seven goals and 20 assists with Hartford of the AHL - the Rangers' top minor league affiliate - during the 2004-05 NHL lockout.