Fresh off his impressive Summer League with the Detroit Pistons in Orlando, Stanley Johnson showed up in Los Angeles at The Drew League on Saturday. He promptly went off for 31 points and 9 rebounds. His running mate was Andre Drummond—also his Pistons teammate—who put up 17 and 12 in the same game. Watch the highlights above. It’s hard not to start thinking that SJ is going to have a major impact in the L…