There was talk of a move to play for MLS side Chicago Fire but those plans are on hold after being offered a five-month deal at Priestfield.
"I can play in the States at a later time in my career. I'm going to channel all my energy into Gillingham Football Club now," Spiller told BBC Radio Kent.
The former Millwall man insisted that the short-term deal suits both parties at the moment.
"They want to see that I'm fit and there's not going to be any hiccups along the way," he said.
If his injury problems are behind him this could work out very well. Fingers crossed as his bite in midfield will be more than handy this season.
Vambogills
"I think it suits them as much as it suits me because it keeps me chomping at the bit and I already want to go out and earn myself a new contract."
Spiller also revealed that Andy Hessenthaler's return to the club persuaded him to also come back for a second spell.
"You always get off to a great start with a manager when you know they want you and you're one of their players that they signed," he said.
"All I want to do now is get my head down and show him that he's made the right decision.
"If I can keep training and playing in the same vain that I have been in the last month or so then I'm sure it's going to turn out to be another successful reign at Gillingham."
Source: BBC Sport
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