Odin Thiago Holm is the only addition to last season’s squad able to train in the Algarve as Rodgers prepares his squad for two matches next week in Japan.
Johnston suffered an ankle injury in the Scottish Cup semi-final win at Hampden on April 30, after the final whistle he was celebrating on his crutches.
The match took place at The Campus next to the holiday resort of Quinta do Lago with a claim that around 100 Celtic fans were hoping to watch the match which the hoops are believed to have won 1-0.
The Campus is very close to the town but the area is designed for high quality training with no spectator facilities or gantries to watch the matches. The message to anyone wanting to catch a glimpse of Portimonense v Celtic is KEEP OUT!
The game at Alloa will be the final warm up match before the Lowland League opener away to Cumbernauld Colts on July 22 which kicks off a busy run of four matches in 10 days against Caledonian Braves, Cowdenbeath and East Kilbride.