A Seahawks spokesman later confirmed the agreement to The Associated Press but wouldn't reveal terms.
"Earl is extremely excited to reach an agreement with the Seahawks and get on the practice field, and we are both very appreciative of the sincere and strong effort put forth by the team to get this contract finalized," Thomas' agent, Andrew Kessler, wrote in an e-mail to The AP.
Thomas posted on his Twitter account late Saturday: "the deal is finally done bout to go sign the paperwork now....ow-w-w let's do it."
Thomas, who likely will start for the Seahawks, said he will be on the field for Sunday afternoon's practice, the third of camp.
That left offensive tackle Russell Okung, the sixth overall pick out of Oklahoma State, as the only unsigned Seahawk.
Curry said Saturday that he doesn't begrudge the two rookies.
"I would just tell them to be patient," Curry said. "What they are asking is their right as players, and they deserve every dollar that they can get. This is the business of the game. The business is all about numbers. When it comes to numbers, you've got to protect yourself, because you never know when this can end for you."
Seven of Seattle's last nine first-round picks have been late for camp.
Notes: Special-teams ace Sean Morey retired before ever playing a game for the Seahawks, a team spokesman announced just minutes before the first camp practice. Morey was a Pro Bowl selection in 2008 with the Arizona Cardinals. He has been a leader in raising awareness of head injuries. Last season, he was named co-chair of the NFL Players Association's concussion and traumatic brain injury committee. ... The Seahawks placed OL Chester Pitts, whom they signed Thursday to a one-year deal worth up to $2 million, on the active physically unable to perform list. Pitts had microfracture knee surgery 10 months ago, and Carroll said it could be two more months before the former Houston Texan returns to the field.
The Associated Press contributed to this report.