However, it has now been confirmed that Niemi is still feeling discomfort and he will undergo more surgery on the wrist next week.
'I'm extremely disappointed that having returned to training, I now have to undergo further surgery," he told the club's offical website.
"However, I'm confident that I can recover from this set-back sooner rather than later.
"I was looking forward to joining the new players who have been added to the squad, who I think are great additions for Fulham.
"I will now focus on my rehabilitation after surgery and look forward to returning as soon as possible."