The 24-year-old is available as a free agent following his release by Brazilian outfit Bahia in November.
He travelled with the Seasiders for their clash at Blackburn Rovers on Saturday and will continue to train with the first-team squad.
Adu is also expected to figure in a behind-closed-doors fixture against Blackpool's highly-regarded youth team on Tuesday.
Caretaker boss Barry Ferguson will be on hand to take in that encounter and make a decision on his future involvement.
Adu was billed as a global superstar in the making during his early days, after landing a contract at DC United when he was just 14 years old, but he has struggled to fulfil his potential.
Ferguson is, however, prepared to offer him every opportunity to impress, with Blackpool in desperate need of a spark to turn their faltering season around.
He said in the Blackpool Gazette: "Freddy is just over to train and I'm going to have a look at him. That's as far as it goes at the moment.
"He's not played in two months and he's just come back from Brazil. We'll see how he does in training."