Two-time European champions Benfica or Turkish side Fenerbahce could face Russian club Spartak Moscow.
Portuguese giants Benfica and Fenerbahce go head-to-head in the third qualifying round, with the first leg in Lisbon on Tuesday, for the right to play either Greek side PAOK or Spartak for one of the six remaining group-stage places.
Changes to the qualifying criteria mean that the top four from each of the English Premier League, Spanish La Liga, Italian Serie A and German Bundesliga last season automatically reached this year’s group stage.
Celtic, the 1967 champions, were handed a kind draw against either Swedes Malmo or Hungary’s Vidi – should they can get past AEK Athens in the third qualifying round.
Four-time winners Ajax will take on Slavia Prague or Dynamo Kiev if they see off Standard Liege, while Dutch champions PSV Eindhoven will face either Azeri outfit Qarabag or Belarusians BATE Borisov.
Benfica, Spartak Moscow, Celtic and Qarabag all played in the Champions League group stage last season.
Draw for the UEFA Champions League playoff round:
Red Star Belgrade (SRB) or Spartak Trnava (SVK) v Salzburg (AUT) or Shkendija (MKD)
Qarabag (AZE) or BATE Borisov (BLR) v PSV Eindhoven (NED)
Young Boys (SUI) v Astana (KAZ) or Dinamo Zagreb (CRO)
Malmo (SWE) or Vidi (HUN) v Celtic (SCO) or AEK Athens (GRE)
Benfica (POR) or Fenerbahce (TUR) v PAOK (GRE) or Spartak Moscow (RUS)
Standard Liege (BEL) or Ajax (NED) v Slavia Prague (CZE) v Dynamo Kiev (UKR)
– First legs to be played August 21/22, second legs August 28/29