Thibault is a 13-year NHL veteran who spent the past two seasons as a backup in Pittsburgh. He had a 7-8-2 record and 2.83 goals-against average in 22 games with the Penguins last season.
Slated to play behind Sabres starter Ryan Miller, Thibault is an upgrade over former backup Ty Conklin, who played in only five games after Buffalo acquired him in February after trading veteran backup Martin Biron to Philadelphia.
Conklin is a free agent this summer.
"Jocelyn will bring veteran experience to our team," general manager Darcy Regier said. "We think he will be a great fit."
The Sabres also re-signed two players, unrestricted free agent forward Michael Ryan to a one-year contract and enforcer Andrew Peters, who signed a two-year deal.
Thibault joins a Sabres team that will be significantly different from last season's President's Trophy-winning squad, after Buffalo lost co-captains Chris Drury and Daniel Briere to free agency Sunday.
Thibault has not been a regular starter since a hip injury forced him to miss most of the 2003-04 season with Chicago. He enjoyed his most productive season in 2001-02, when Thibault helped the Blackhawks to their most recent playoff berth, while registering a career high in wins with a 33-23-9 record, six shutouts and a 2.49 goals-against average.
He has a career record of 235-234-68-5, with 37 shutouts, and was an all-star selection in 2003. Thibault broke into the NHL with Quebec during the 1993-94 season. He also played for Montreal.
Peters is a three-year veteran, who had a goal, an assist and 125 penalty minutes in 58 games last season. A restricted free agent whose rights were retained by Buffalo last month, Peters declined to opt for arbitration after making US$460,000 last season.
Ryan, a career minor-leaguer, was an unrestricted free agent after making his NHL debut last season, posting three goals and two assists in 19 games with Buffalo. Ryan will have a shot to become a Sabres regular following the departures of Drury and Briere.
"Michael is a young player who is ready to play full-time at this level," Regier said. "He continues to develop and will be an important part of our club next season."
In separate news, Sabres forward Derek Roy and defenceman Nathan Paetsch opted for arbitration Thursday. They were among 29 NHL players who filed for arbitration.
Roy is projected to receive a considerable raise from the $627,000 he made last season, his third in the NHL. The third-line centre had career highs with 21 goals and 63 points in 75 games. Roy benefited from playing alongside high-scoring wingers Thomas Vanek and Maxim Afinogenov.
Paetsch, who made $495,000, had two goals and 22 assists for 24 points in 63 games in his first full NHL season. He was used mostly as Buffalo's seventh defenceman, but showed signs of being an effective power-play specialist.
Players can negotiate new contracts before their arbitration hearings.