Marseille coach Eric Gerets accepts there is now a gaping hole in his squad's attacking arsenal following the departure of striker Djibril Cisse.
The France international completed his season-long loan move to English side Sunderland on Thursday.
Although Cisse was dropped by Gerets for OM's last match, Sunday's 4-0 win over Auxerre in Ligue 1, the Belgian was counting on rotating the 27-year-old with chief striker Mamadou Niang throughout what could be a busy campaign for the Mediterranean side.
Although OM president Pape Diouf claimed earlier this week the squad was big and talented enough to cope with the loss of Cisse, Gerets admits it has left him in a bit of a quandary.
He could now dip into the transfer market, with just over a week left before the summer window closes.
'With Cisse, the balance was perfect,' said Gerets.'I had a back-up solution for every position and that gave me a certain comfort.
'Obviously, I knew for two months that he wanted to leave the club. We tried to keep him but he decided otherwise.
'It is a shame and it poses us a problem because three matches are coming up back to back. And he would have played in these because Niang needs to rest.'
Baky Kone, a summer signing from Nice, and France Under-21 international Elliot Grandin are the only other attackers in OM's squad, but they are both diminutive forwards who would not be comfortable leading the line should Niang suffer an injury.
That means Gerets will probably seek a replacement for Cisse in the coming days.
'We are looking for a number nine who is younger than Grandin (who is 20), but who has a more athletic physique than the calibre we have at the moment,' he added.
Meanwhile, Diouf has revealed Sunderland have the option of signing Cisse on a permanent basis once his loan spell ends.
'The negotiations took a while because we wanted just a simple loan,' Diouf said.
'But Sunderland wanted to add the option, and that is why the discussions took longer.'