Atlanta manager Brian Snitker noted Friday that Riley (side) is likely to remain out until Monday's series opener against the Nationals, Mark Bowman of MLB.com reports.
Riley has been sidelined due to a left intercostal strain he sustained May 12 against the Mets. Despite the length of his absence, Atlanta did not place the 27-year-old third baseman on the 10-day IL in hopes he could return sooner, but Riley appears on track to rejoin the lineup following a weekend series against the Pirates. Prior to his injury, Riley was slashing .245/.319/.388 with eight doubles, three home runs and 18 RBI over 163 plate appearances.