PHILADELPHIA — The Braves put rookie starting pitcher Aaron Blair on the 15-day disabled list for a left knee strain and recalled reliever Brandon Cunniff, who was back from Triple-A and in Atlanta’s bullpen for Saturday night’s game against the Phillies.

Since the Braves had already said last week the struggling Blair would not pitch in games for a while and would instead work on some problems in his delivery. Roster spots aren’t an issue, since major league rosters can be expanded in September and Blair’s position on the active roster wasn’t “wasting” a spot at all.

Instead, the decision to DL him Saturday was made so the Braves could add a bullpen arm by recalling Cunniff only four days after optioning him to Triple-A Gwinnett. A player optioned to the minors can’t be recalled for 10 days unless another player on the major league roster goes on the DL.

Blair spent 2 ½ weeks on Gwinnett’s DL last month after his knee gave way and he collapsed during a mound session. Initially the Braves feared a severe injury, but tests results shown no damage and he was back by late August and then brought up by the Braves to start last Sunday at San Francisco. The knee hasn’t worsened since his minor league DL stint.

He gave up eight hits, five runs and three homers in four innings of a loss to the Giants, falling to 0-6 with an 8.23 ERA in 12 starts for Atlanta. Blair is 0-4 with a 10.64 ERA and 18 walks in 34 2/3 innings over his past eight major league starts, and gave up 10 homers in 27 2/3 innings over his past six.

Braves interim manager Brian Snitker said the Braves plan to have Blair pitch again this season, either as a starter or reliever, once he’s comfortable with adjustments being made in his delivery. The DL designation hasn’t changed anything in that regard; the work he’s doing with pitching coach Roger McDowell continues.