How many games Premier players will miss because of AFCON ultimately depends on just how far both teams will go. So, should Egypt and Senegal go all the way, Salah and Mane will miss potentially nine games at least, five of which will be Premier League games, the others being two FA Cup ties and the Champions League round of 16 first leg. All three of the latter games have yet to be announced but are penciled in for January and February.
Senegal are in a group containing Zimbabwe, Guinea, and Malawi, and considering the top two advance from the group with another place up for grabs for third-placed teams based on rankings, it would be an upset if Edouard Mendy, Mane and co. didn't make it through.
Egypt, while not boasting anywhere near the talent of nations like Algeria and Senegal across the pitch, are still expected to make it through to the knockout rounds from Group D. Salah and his colleagues will meet with Nigeria, Sudan, and Guinea-Bissau where Egypt should make it through in first or second.
Group games are set to be from January 9th up until January 20th, where if a nation doesn't make it through, they will head straight back to their clubs shortly after. Players will be able to get some time off after the AFCON, but this ultimately comes down to player and club deciding this amongst themselves, as there is no rule from FIFA that states they can't begin playing again straight away.
FIFA do, however, state “players must be released and start travel to their representative team no later than Monday morning the week preceding the week when the relevant final competition starts.”
So, how many games will Salah and Mane miss will depend on two things: how far they go and if they want to rejoin Liverpool straight away. Nevertheless, Premier League players will depart during the Boxing Day games at the latest and be in action in Cameroon until at least January 20th with the group games ending that day.