Ryder, 33, collected 16 goals and 19 assists for 35 points in 46 games with the Dallas Stars and Montreal Canadiens last season.
In 667 career NHL regular-season games with the Canadiens, Boston Bruins and Stars, Ryder has accumulated 213 goals and 218 assists for 431 points.
Ryder was originally drafted by the Habs in the eighth-round (216th overall) of the 1998 NHL Entry Draft.
Olesz, 27, will enter his ninth year in North America, after spending the 2012-13 season with Rockford (AHL).
He has career totals of 57 goals and 75 assists for 132 points and 118 penalty minutes in 355 NHL regular-season contests.
Olesz was Florida's first choice, and seventh overall selection in the 2004 NHL Entry Draft.