CLEVELAND—Baker Mayfield moved a step closer to playing against Aaron Rodgers on Christmas as the Browns activated their quarterback from the COVID-19 reserve list Friday before leaving for Green Bay. Mayfield has been out since testing positive on Dec. 15, one of a slew of virus cases the past two weeks for the Browns. He missed Monday’s game against Las Vegas as Cleveland started third-string QB Nick Mullens, numerous backups and lost. Mayfield hasn’t practiced in nearly two weeks, but coach Kevin Stefanski, who returned earlier this week after his second positive test in two seasons, said Thursday he anticipated Mayfield starting against the Packers (11–3) as the Browns (7–7) try to bolster their flimsy playoff chances. The virus continued to wreak havoc across the league, forcing teams to make adjustments in the season’s final weeks. Indianapolis All-Pro guard Quenton Nelson and Jacksonville pass rusher Josh Allen were the most …