Adam Wainwright and Jaime Garcia also are expected to be back next year, but Chris Carpenter is coming off surgery to relieve nerve compression in his shoulder and Kyle Lohse is eligible for free agency.
Cardinals general manager John Mozeliak said Tuesday there have been no talks to date with Lohse, who is 12-2 with a 2.61 ERA in 25 starts this season.
"I don't want to guess on what conversations may look like or may happen, but the key thing for me today is knowing that the Jake Westbrook deal is done," Mozeliak said. "In terms of future negotiations or talks, we'll obviously be open to that but right now we're just happy we got this one done."
The 34-year-old Westbrook is 12-9 with a 3.50 ERA in 24 starts this season, leaving him three shy of 100 career victories. The sinkerballer leads the National League with 22 double plays induced and is also the best in the league at getting ground balls at 73 percent.
"I'm super excited to get this done," he said. "It gives me peace of mind knowing I'm going to be back here last year."
Westbrook is in his second full season with the Cardinals, who acquired him in a deal with the Indians at the 2010 trade deadline. The Cardinals and Westbrook had a mutual option for next season before the new deal.
"When you think back to that trade, a lot of people were second-guessing why we were doing it," Mozeliak said. "Clearly, he's been a very stable member of this rotation."
Westbrook shed about 20 pounds in the offseason after going 12-9 with a staff-high 4.66 ERA and sitting out for much of the Cardinals' World Series run. He wasn't on the roster for the NL Division and NL championship series and played a minor role in Game 6 of the World Series, getting the victory with an inning of scoreless relief.
"I think that's one of the reasons that I worked so hard in the offseason, to give myself every opportunity to prolong my career," Westbrook said. "I definitely don't want to stop playing."