Clement, 33, was pitching for the team's Triple-A affiliate in Memphis, going 1-0 with a 4.61 ERA in 12 games. He did not make a start, totaling 13 2/3 innings, and had allowed three home runs. The move leaves the Cardinals with an open spot on their 40-man roster.
"We just felt like he wasn't making the progression that we thought he would, and ultimately it came down to taking innings away from some guys who we feel need it," general manager John Mozeliak said. "We tried to be as patient as we could during this process and I can tell you he worked extremely hard to get back, but in the end it just wasn't there."
The Cardinals signed Clement to a $1.5-million, one-year contract in January with a club option for next season. He's 87-86 with a 4.47 ERA in nine major league seasons and was an All-Star in 2005 with the Red Sox, and made at least 30 starts in seven straight seasons from 1999-2005 before encountering shoulder problems.
The Cardinals had envisioned him as part of a rebuilt rotation, but he never developed consistency in velocity or pitch movement. Mozeliak said Clement hit the mid- to upper-80s at times.
"It just was more or less kind of the overall picture we didn't think was going to help us get to where we wanted to be," Mozeliak said. "He was trending up at times but he never was able to sustain it."