The Reds, third on the table, face on fourth-placed Melbourne Victory away from home on Saturday evening. Four days later Victory must be in China to play ACL holders Guangzhou Evergrande in their group stage opener.
Western Sydney Wanderers and Central Coast Mariners are also set to juggle the same gruelling sequence of matches, potentially opening the door for Adelaide to capitalise.
"When you play two competitions, (it) is difficult," Gombau said.
"Now they're (at the) start. But when you are playing in the group - I speak with experience, because I played the AFC (Champions League) with Kitchee. And we had three competitions, cup, AFC plus league. And ... you need to start (to) make rotations because (of) so many games. This can happen to them. They start now, and the first game is not like this.
"But ... the teams that are playing the Champions League need to fight to be in the top two in the group, to go to the next round. In that moment you need to start to think a lot."
Gombau does not expect ACL obligations to distract Victory ahead of this weekend's clash at AAMI Park, but believes the effects could be felt by time Adelaide travel to take on the Wanderers in Round 23.
"I think this week (it) won't affect them but in the next games the three teams that are playing AFC Champions League, it will affect them, sure," he said.
"Because you are playing another competition and more games, more pressure. The other competition is so important. And in that moment, as a coach, you need to start to make some rotations.
"Maybe next (month), when we play against Western Sydney, in that moment they are involved in the competition. Two or three games in (it will affect them)."
