General manager John Mozeliak said Tuesday he sent a letter to Mulder's agent, Gregg Clifton, informing him of the franchise's intention. The Cardinals had until Nov. 15 to notify Mulder.
"We don't have to do anything yet, but the likelihood is we will buy him out," Mozeliak said.
Mozeliak said he didn't think the Cardinals would be interested in re-signing Mulder at a lower rate, either.
"There's always that chance," Mozeliak said. "But right now we're trying to focus on looking for guys who aren't going to be health risks."
The Cardinals' rotation for next season includes Adam Wainwright, Kyle Lohse, Todd Wellemeyer and Joel Pineiro. Ace Chris Carpenter would head that list if he's able to recover from a nerve problem that affects the muscles in the back of his shoulder and around his neck.
Earlier this month Carpenter and the team decided against surgery, opting for therapy and rest.
Mulder, 31, is rehabbing from a pair of shoulder operations and was limited to 1 2/3 innings last season after initial optimistic forecasts he could join the rotation as early as May. He made $13 million the last two seasons while totaling six appearances and four starts covering 12 2/3 innings.
Mulder had two rehab assignments last season, was activated as a reliever and made one start in July that lasted only 16 pitches. He made three starts in September 2007, going 0-3 with a 12.27 ERA before undergoing a second shoulder surgery.
The Cardinals sent young right-hander Dan Haren and a top prospect to the Oakland Athletics for Mulder before the 2005 season. Mulder won 16 games his first year but was 6-10 with only 21 starts the last three seasons.
Mozeliak told the St. Louis Post-Dispatch that Mulder's situation has taught the team not to bet on injury recoveries in the future.
"When we look at next year, I'm going to be very cautious not to allow us to go
down the same path that we did last season with players and injuries," Mozeliak told the newspaper. "You have to have some assurances. You're only one
injury away in this game, and I think we have to do what we can to minimize
that [exposure] as much as possible."
The No. 2 overall pick in the 1998 amateur draft, Mulder has a 103-60 career record in 205 appearances for the Cardinals and A's, who drafted him out of Michigan State. A two-time All-Star, he led the American League with 21 wins in 2001 and finished second in balloting for the AL Cy Young Award that season.
Information from The Associated Press was used in this report.