Ba has been without a club since leaving AC Milan over the summer and he had appeared for the Trotters on their tour of Malta, in which he scored in the 5-1 win over Floriana and in the recent home friendlies against Real Mallorca and Olympiakos but he will now be forced to try his luck elswhere.
He joins Tomasz Klos, Fousenni Diawara and Rene Bolf in being unsuccessful during trial spells at the Reebok Stadium over the summer and for Allardyce it is very much back to the drawing board in his search for new blood as the August transfer deadline looms ever closer.