Riley is out of the lineup for Monday's game against the Cubs and is slated to undergo an MRI on his injured left side, David O'Brien of The Athletic reports.
Elder pitched well in Sunday's loss to the Mets but did not factor into the decision. He allowed two runs on seven hits and no walks while striking out six in 5.1 innings.
Riley (side) isn't overly concerned with his long-term availability after being removed early from Sunday's game, and he considers himself day-to-day, Justin Toscano of The Atlanta Journal-Constitution reports.
Riley was removed from Sunday's contest against the Mets in bottom of the fourth inning with left side tightness, Justin Toscano of The Atlanta Journal-Constitution reports.