David Warner has been ruled out of the ongoing second Test against India at the Koltla after suffering a concussion when he was struck in the head while batting on Day 1, Australian media reported on Saturday.Matt Renshaw has been brought into the Australia team as a concussion substitute.Australia, who suffered a heavy defeat in the opening Test in Nagpur, were dismissed for 263 in their first innings in the 2nd Test on Friday.Warner faced a bouncer barrage from Mohammed Siraj and was hit twice - once on his arm and then on his helmet - needing medical assistance.