Jalen Johnson is expected to be called up Friday from the G League, sources say, because of John Collins’ injuries to his finger and foot that will sideline him indefinitely and Danilo Gallinari’s bruised bicep that has him listed as questionable for Friday’s game against Memphis. Collins’ unavailability isn’t new though. He’s missed 10 of the past 14 Hawks games entering Friday, and Johnson hasn’t sniffed the rotation. Nate McMillan has used Gallinari, De’Andre Hunter, Timothe Luwawu-Cabarrot and Kevin Knox at power forward, with Johnson notably absent.