Jennings' contract wasn't set to expire for another three seasons, which means Miami could still owe him money unless he's hired elsewhere and his salary is offset.
Jennings, 55, hasn't managed to turn the Marlins into a competitive club again, but he's been challenged with (perhaps overly) high expectations each season. He remains a well-respected executive and has already attracted interest from clubs looking for assistant general managers.
Bob Nightengale of USA Today adds that Jennings was actually hoping to leave Miami for other opportunities, which could help explain the surprise move despite Jennings' close relationship with owner Jeff Loria.
Here's the other interesting buzz making its way around the majors:
Minnesota Twins: Torii Hunter's decision to retire has dramatically impacted the Twins' approach to the offseason. According to La Velle E. Neal III of the Minneapolis Star-Tribune, Minnesota had been planning their offseason under the assumption that Hunter would return in 2016. Neal tweeted that some organization officials are "crushed" by Hunter's decision. Twins assistant GM Rob Antony stressed how important Hunter's leadership role was in the clubhouse this season.
Detroit Tigers: Rich Dubee joins the Tigers as their new pitching coach, the club announced. Dubee, 58, has spent the last two seasons as the Atlanta Braves' minor league pitching coordinator. He replaces pitching coach Jeff Jones, who retired at the end of the season. Tigers GM Al Avila said of Dubee's hire, "I've known Rich Dubee way back from the Florida Marlin days, and I can tell you we're very excited to have him. Rich brings the knowledge and experience to deal with veteran Major League starters, but he also comes from a background of developing young talent. So he's got that combination that we all look for."