Mahle (hamstring) will be sent to Triple-A Louisville to begin a rehab stint Friday, Bobby Nightengale of The Cincinnati Enquirer reports.
Mahle is on track to toss two innings Friday, assuming Tuesday's bullpen session goes as planned. He's been on the shelf for just over three weeks, and with Cincinnati intent on bring Mahle back as a reliever, he won't need much time to build up and get his arm back in shape.