Icardi has joined PSG from Inter on a season-long loan with an option for a permanent deal and is in contention to make his Ligue 1 debut against Strasbourg on Saturday.
His arrival further bolsters a forward line that already includes Kylian Mbappe, Angel Di Maria and Neymar, who is available after the closure of the transfer window ended his chances of returning to Barcelona.
Tuchel now faces a balancing act when it comes to team selection, though the club's record goalscorer Cavani and World Cup winner Mbappe will both sit out the visit of Strasbourg due to injury.
"He has to get back to his rhythm, he's a number nine like Edi," Tuchel told reporters of Icardi, who was stripped of the Inter captaincy last term.
"He's here, he's very happy to be here, I feel like he's free, and tomorrow it might be the first game where we can use him.
"I do not know if he's ready to play 90 or 60 minutes, but the competition helps us, my team.
"I do not see them as competitors on a job but as accomplices. We can play with Mauro and Edi in a match, I expect from my team that we have a good mindset to work in.
"If we have a lot of attackers, it is necessary that they be accomplices, even if everyone wants to play."
Mbappe and Cavani are not expected to be fit for next week's visit of Real Madrid when the Champions League group stage gets under way, with Neymar ruled out of that match due to suspension.
Pressed further on juggling his strikeforce, Tuchel said: "We cross that bridge when we come to it.
"We do not have Kylian or Edi, we will not have Neymar for Madrid.
"I have a lot of options in my mind, but we're not there yet.
"But we do not achieve high goals without hard choices."