Right-back Fredericks set up nine goals en route to promotion via the Championship play-offs this season, and is said to have been courted by a string of Premier League clubs.
However, if the 25-year-old is to walk out on Fulham, their new found riches should ensure it is not the end of the world.
Here are three players they should consider to replace him...
Moritz Bauer (Stoke City)
Signed by Stoke for around £5 million in January, the Austrian impressed despite his side's relegation to the Championship. Fulham could offer the 26-year-old an immediate return, although he admitted earlier this month that he wanted to stay at the Bet365 Stadium regardless of the Potters' fate.
Joel Ward (Crystal Palace)
A veteran of 163 Premier League appearances and out of contract at Crystal Palace, Ward is certainly the most experienced and cost-effective option on this list. However, reports this week claimed he could be ready to commit to the Eagles despite being offered a pay cut - an incentive perhaps for Fulham to move fast.
A player Fulham should know well, given his battles with them for Leeds United, Ayling would probably fancy another stab at top flight football, after being released by Arsenal earlier in his career. However, with a contract until 2021 and key player status at Elland Road, he could be difficult to prise away.
Who would you sign to replace Fredericks should he leave for West Ham United?
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