Wainwright will miss the start because of tendinitis in his pitching elbow. He is 9-3 with a 2.15 ERA in 100 1-3 innings this season. He had an injection on Wednesday after an MRI pinpointed the trouble area in the back of his elbow. General manager John Mozeliak said it was like ''tennis elbow.''
Wainwright was a 19-game winner last year and won 20 games in 2010.
This season, Martinez is 0-3 with a 4.67 ERA in 30 appearances with no starts. He started one game in 2013. He went 4 2-3 innings against the Los Angeles Dodgers, allowing four runs.
The Cardinals also have purchased the contract of left-handed pitcher Nick Greenwood from Triple-A Memphis and optioned outfielder Randal Grichuk back to the affiliate.
Greenwood was 3-3 with a 2.61 ERA in 22 games (three starts) for Memphis this season. In 41 1-3 innings, he held opponents to a .221 average. Greenwood, a native of Farmington, Connecticut, was 1-0 with a 0.82 ERA in three games started, the most recent on June 1 at Oklahoma City.
The 26-year-old Greenwood will be making his major league debut with his first appearance, becoming the fifth player to debut with the Cardinals this season, joining Grichuk, Greg Garcia, Eric Fornataro and Oscar Taveras.
A veteran of 218 minor league games (47 starts), Greenwood was acquired by the Cardinals from San Diego on July 31, 2010, in a three-way trade with the Padres and Cleveland Indians that also sent pitcher Jake Westbrook to St. Louis.
Grichuk, 22, is hitting .136 in 19 games with one home run and three RBIs. Grichuk was recalled May 30 when the club optioned outfielder Shane Robinson to their top farm club. Grichuk was batting .315 with 32 RBIs at Memphis when he was recalled.
The Cardinals acquired Grichuk, a first-round draft pick by the Angels in 2009, in an offseason trade. He was 3 for 21 in an earlier stint with St. Louis, making four starts before getting sent down May 7.