The NHL and NHLPA made the announcement Wednesday.
The Senators issued a statement from general manager Pierre Dorion saying, “Bobby is an important member of the Ottawa Senators family and he has our full support as he tends to this matter.”
The 32-year-old Ryan did not play for Ottawa in a victory in Detroit on Tuesday, one day after leaving practice early because he was not feeling well, according to coach D.J. Smith.
The No. 2 overall pick by Anaheim in the 2005 draft, Ryan has one goal and three assists in 16 games this season.
The Senators acquired Ryan in a trade with Anaheim in July 2013, on the same day they lost franchise player Daniel Alfredsson to the Detroit Red Wings in free agency.