Gbison's deal is worth $12 million next season, sources told ESPN.
Gibson, 36, spent last season with the Baltimore Orioles, going 15-9 with a 4.73 ERA in 33 starts. He threw 192 innings while giving up a league high 198 hits. After spending the first seven years of his career with the Minnesota Twins, the veteran is joining his fourth team in four years. Overall, he's 104-100 with a 4.54 career ERA in 11 seasons.
Gibson joins a rotation with holdovers Miles Mikolas and Steven Matz along with newcomer Lynn. St. Louis ranked 26th in starter's ERA last season and weren't shy about the need to add to their rotation after trading Jack Flaherty and Jordan Montgomery during the season combined with the retirement of Adam Wainwright.
Lynn and Gibson will add valuable innings to a team that could still use a top of rotation type pitcher.