Ortiz is believed to be the most expensive player to be cut loose in baseball history.
The club designated the struggling right-hander for assignment, which means it has 10 days to trade, waive or release him. The team is on the hook for the balance of the $33 million, four-year contract Ortiz signed in December 2004, a figure general manager Josh Byrnes said was close to $22 million.
The 32-year-old Ortiz was 0-5 with a 7.54 ERA in six starts for Arizona this season, and he was 1-14 in his last 19 starts dating to last May.
"We're like most clubs: Every dollar counts. You want to spend them as effectively as possible," Byrnes said at a Chase Field news conference. "That affected the decision, but we also were true to ourselves, and we want to put our best 25 on the field and try to win games. That led us to our decision.
"We have to spend all our dollars wisely, and obviously we owe Russ a lot of money going forward," Byrnes said. "The flip side is we probably have more young talent than anyone in baseball, and that's a good thing as managing the payroll."
In a corresponding move, the club purchased the contract of left-hander Randy Choate from Triple-A Tucson. Choate, who was 3-0 with five saves and a 2.45 ERA in Tucson, will pitch out of the bullpen. The Diamondbacks haven't announced who will take Ortiz's slot in the rotation Saturday at Texas.
Ortiz's ouster comes during a tumultuous 11-day homestand for the Diamondbacks, who led the NL West by 2½ games when they returned from a 7-3 road trip June 4.
Heading into Tuesday night's game against San Francisco, the Diamondbacks had dropped the first seven games of the homestand and fell one game behind Los Angeles.
One of the losses was a three-hit complete game by New York's Orlando Hernandez, who was traded by Arizona two weeks earlier.
Last Tuesday, the Diamondbacks were blindsided by news reports that federal agents had searched Jason Grimsley's Scottsdale home June 6 in an investigation into performance-enhancing drugs. The team released the reliever last week and doesn't want to pay him the remainder of his $825,000 salary. Grimsley was suspended Monday for 50 games by commissioner Bud Selig.
"There were a lot of things going on for a team that was playing pretty well," manager Bob Melvin said. "More than anything, we just want to get settled."
On Sunday, Ortiz was booed heavily by the Chase Field crowd as he gave up five earned runs in 3 1/3 innings of an eventual 15-2 loss to the Mets, which completed a four-game sweep.
Melvin said he thought Ortiz's mechanics had improved after a recent minor-league stint but added that the pitcher had "a lot of baggage" here.
"It's tough to get through sometimes that when you've struggled in one particular place for so long," Melvin said. "The change of scenery might be the best thing in the world for him. He could clear his head, and he doesn't have some of the negativity in the record and so forth that he had here. We wish him the best and hope that the next place is a better place for him."
Ortiz was not immediately available for comment.
He was signed in December 2004, one day after Arizona gave free-agent third baseman Troy Glaus a $45-million, four-year deal. The deals created a buzz over the aggressive rebuilding strategy by the ownership group that took control in August 2004, near the end of a 51-111 season. Nineteen months later, both players are gone. After one year, the Diamondbacks dealt Glaus to Toronto for pitcher Miguel Batista and second baseman Orlando Hudson, who have both contributed this season.
When Ortiz arrived in Arizona, he had a career 103-60 record and had never been on the disabled list. He spent parts of each season with Arizona on the disabled list, with a rib cage injury in 2005 and a calf injury this year.
But even when Ortiz was healthy he was ineffective, and the Diamondbacks finally ran out of patience.
"We tried a lot of different things and it just wasn't working, so we decided to give someone else a shot," Byrnes said.