The 26-year-old D'Agostini has 47 goals and 48 assists in 267 career games with Montreal, St. Louis and New Jersey. He split time with the Blues and Devils in 2013, collecting three goals and three assists in 29 games. D'Agostini scored a career-high 21 goals for St. Louis in 2010-11.
D'Agostini says he'll "fit into any role that Pittsburgh wants from me." He has spent time on both scoring lines and checking lines during his career.