Financial terms weren't announced.
Del Zotto spent part of the 2018-19 season with Anaheim before being traded to the eventual Stanley Cup champion Blues.
The 29-year-old is in a much different place than when he was a mainstay on the Rangers' blue line at age 19. After four-plus years there, he fell out of favor and has been on five teams in the past six years.
No season was more of a journey -- literally -- than this past one. He started with Vancouver but was traded in January to Anaheim.
At the trade deadline he was then dealt to St. Louis. The Blues were just starting to turn it around at the time, but Del Zotto didn't get to play much of a role. He played in seven regular-season games and didn't suit up in the playoffs.
Del Zotto is coming off a two-year, $6 million deal he signed with Vancouver. Between the three teams last season he had 10 points in 42 games.
His best season was as a 21-year-old in New York, when he had 10 goals and 31 assists in 77 games in 2011-12 and helped lead the Rangers to the conference finals.