Ebner was given permission from the Patriots to leave to begin training at the U.S. Olympic training facility in California. Ebner is scheduled to rejoin the Patriots after the Aug. 6-11 Olympic rugby competition.
"First and foremost, I want to thank the Patriots from top to bottom for giving me the opportunity to come back and play for a truly first-class organization," Ebner said.
The Patriots officially re-signed Ebner, who was unrestricted free agent, to a two-year contract on Tuesday. Financial terms were not disclosed.
"I also want to thank them and USA Rugby for giving me the opportunity to chase a dream I've had since I was a boy in a sport in which I've always had a passion," he said. "I can't put into words how much this opportunity means to not only me, but my friends and family as well.
"I plan to represent the Patriots and our country to the best of my ability. Thanks again and Go Pats and go USA."
In a conference call with reporters Tuesday, Ebner said he realizes his participation in the Olympics isn't a lock.
"I am absolutely not guaranteed a spot," he said. "I have to try out for the team like anybody else and I have to earn a spot like anybody. I'm just lucky to even have the opportunity to even try."
The Patriots tweeted their support on Tuesday.
"We are grateful for the support of coach Bill Belichick and the entire New England Patriots staff for their support of USA Rugby and Team USA,"USA Rugby performance director Alex Magleby said in a statement.
Ebner was an All-America rugby player at Ohio State before the Patriots selected him in the sixth round of the 2012 draft.
"We are excited and looking forward to Nate joining the program and working with the squad. We are aware of Nate's rugby background from his high school and college days and this was the key to him being in a position to compete with the current squad," USA Rugby Men's Sevens Head Coach Mike Friday said in the statement.
In his conference call, Ebner called this a "unique" opportunity, one that "would be unlike anything I've ever experienced" and something "I would never forget for the rest of my life."
"Growing up playing rugby, we didn't have the opportunity to play in the Olympics. The biggest thing you could go to was the World Cup because rugby wasn't in the Olympics but to see it back in the form of Sevens in 2016 in Rio, just the idea of being a part of the Olympics would be humbling and amazing," he said.
ESPN's Arash Markazi contributed to this report.
Nate Ebner takes leave from Patriots for Olympic rugby
ESPN Patriots reporter Mike Reiss discusses Patriots safety Nate Ebner's decision to leave the team temporarily to play rugby in the Olympics.