Aardsma, who has been out for the last two months following surgery to repair a torn adductor muscle, is expected to begin a rehab assignment by the end of the week, Derrick Goold of the St. Louis Post-Dispatch reports. Prior to succumbing to the groin injury, Aardsma was making a strong case for a promotion to the big leagues, accruing a 0.91 ERA over 28 games with Triple-A Memphis. The veteran reliever has made significant strides in recent days, throwing two live batting practice sessions. It may not take much longer for him to slot back into the Memphis bullpen, and if he reclaims his earlier form quickly, look for him to be added to the St. Louis roster as a September call-up.