The 25-year-old spent the 2013 NFL pre-season with the Buffalo Bills but didn't feature in a regular-season match for the club.
Following his release by the Bills, Kaufman was spotted by Suns recruiters who were impressed by his athleticism and handling skills as a wide receiver.
The Denver, Colorado product stands at 196cm and has shed 9kg during enhanced endurance training to tip the scales at 96kg.
"I picked up a Sherrin for the first time in November and, since then, there hasn't been a day where I haven't learnt something new," Kaufman said.
"I'm beginning to feel more comfortable with the Sherrin in my hands and I've still got time to keep getting better and better."