Mikael Arteta is prepared to let Lacazette leave, while new Barcelona head coach Ronald Koeman does not see Umtiti as a player who will fight for a place in the starting XI next season.
A romantic return to Lyon has been mentioned for both, with Juninho admitting to having spoken to Lacazette in January, but it appears the idea of any deals is wishful thinking due to their large contracts.
"In January I called Alexandre Lacazette to chat a bit with him because he was having problems at Arsenal and I said to myself, 'Why not do a loan for six months with us where you will enjoy yourself, play all the games and score the goals like you know how to? And then you go back to Arsenal or somewhere else'," the Brazilian said in an interview with RMC Sport.
"But from the moment that you start looking at the level of the contract of these players, like with Juventus and Barcelona, it is not possible for us today.
"Today, we have to tell the truth, we cannot pay the salary for a player like Umtiti.
"We have to be honest with the supporters. But if the player is looking for a project, is willing to make an effort maybe with a longer contract, wants to come home, then I will go and get him straight away."
Lacazette had been linked with a move to Juventus a few weeks ago, but any move to Turin now appears to be dead, with the Serie A champions set to complete the transfer of Luis Suarez from Barcelona.
The Frenchman scored 10 Premier League goals in 30 appearances last season.