The team expects the right-hander, 9-3 with a 2.15 ERA, to return next Saturday against the Phillies. If this were October, general manager John Mozeliak said, Wainwright would definitely take the ball.
"I think this is more precautionary than anything else," Mozeliak said Saturday night's game against the Nationals. "It was something that we just didn't want to push if we didn't have to, and he agreed."
A day earlier, Wainwright emphasized his surgically repaired ligament was structurally sound and that the inflamed area was very small. Wainwright, who missed the 2011 season, won 19 games for the second time in his career last year and won 21 games in 2010.
Reliever Carlos Martinez will take Wainwright's spot and make his second career start. 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.
Wainwright said the elbow has been bothering him the past two starts, although it didn't affect his performance given he won both games and allowed two runs in 15 innings.
In between those outings, the pitcher said the elbow was "very sore."
So he told the training staff.
Wainwright is tied for the National League lead with nine wins and was second in the NL with 100 1-3 innings, working at least seven innings in all but three of his 14 starts.
He led the league with 241 2/3 innings last year and then tacked on another 35 innings for a team that lost to the Red Sox in the World Series.
The curveball, his best pitch, puts extra stress on the elbow.
Wainwright played catch inside earlier in the day and felt better, three days after receiving a cortisone injection, but Mozeliak said the right-hander understood the decision.
Both the pitcher and team said a day earlier that it was prudent to take the long-term view.
The Associated Press contributed to this report.