Griffiths won't be with the Celtic squad to take on Lyon, Nice and PSG.
The SPFL have announced the fixture list for the coming season.
Fraser Forster has decided to fight for a first-team place at Southampton.
The 37-year-old has officially ended his six-year stay at Parkhead.
The Scotland captain is an English league champion after Liverpool topped the table.
The first Scottish Premiership clubs return to action after three months off due to the coronavirus pandemic.
The Parkhead club have been awarded the Scottish Premiership title.
Celtic FC Foundation will use the money donated to 'put food on the table, as well as to distribute urgent essentials'.
46-year-old underwent emergency surgery earlier this year after suffering a brain haemorrhage.
The Rangers boss wants an independent investigation into the SPFL's handling of the matter.
Matthew McCombe, 21, disappeared in Amsterdam during the early hours of March 14.
Matthew McCombe, 21, disappeared in Amsterdam last Saturday morning.
The Scottish FA says it intends to complete the cup matches in front of supporters.
The Celtic boss says sport is secondary to the human cost of coronavirus.
The SFA and SPFl have taken the decision to cancel all games with immediate effect.
Celtic hold a 1-1 draw from the first leg of their Europa League tie against Copenhagen.
Fraser Forster saved a penalty to ensure the sides are level ahead of next week's decider.
The Glasgow clubs will experience VAR for the first time in the Europa League last 32.
Pieros Sotiriou is travelling to sign for Astana instead of facing the Scottish champions.
Celtic edged a 2-1 win against Aberdeen in blustery conditions after a late Kristoffer Ajer strike.