The Serbia global played a key role in Chelsea's title-winning campaign last term alongside PFA Player of the Year N'Golo Kante.
Costa, who scored 20 goals last season as the Blues won the Premier League glory, has been linked with a move to Atletico Madrid who are now under a transfer ban.
Conte went on to reveal that he remains undecided whether to start Morata in his side's Premier League opener at home to Burnley tomorrow. This is my message.
Pedro's absence and Chelsea's general shortage of options could force Conte to start Morata alongside Michy Batshuayi against Burnley, though he admitted the Spain global is still some way off being fully adapted to his tactical demands.
Conte added: "There could be an opportunity to start the game for Rudiger because Moses will miss out for one game". The situation is clear.
"If the club decide to send on loan players for their development it's because these players are not ready to play for Chelsea".
Arsenal manager Arsene Wenger had an answer, pointing to Chelsea sending numerous players out on loan, but Conte insisted: "I'm not looking for sympathy of any coaches for this situation".
"It's simple. I think I'm the coach of this team". The other teams will try to give 120 per cent against us.
"If Conte needs a few players, the best thing is for the club to do that.' Crespo told Daily Mail".
"I repeat: my only task is to focus on the pitch, what happens on the pitch, during the training session to work with my players".
"The striker is an important role".
The striker then dons a multi-coloured wig, much to the children's enjoyment, and again begins to rock out.
Liam is ESPN FC's Chelsea correspondent.