Carroll said Monday on 710 ESPN Seattle that Lynch will "be flying in there this morning, and we're going to give him a really good chance to come back and play for us."
After meeting with Carroll, Lynch was expected to take a physical on Monday.
Lynch spent parts of six seasons with the Seahawks from 2010 to 2015. The five-time Pro Bowler played for the Oakland Raiders in each of the past two seasons before reportedly retiring this past April.
Lynch has not filed retirement paperwork with the league, but he has not been linked with any team this season.
"He's been working really hard," Carroll said. "He's really excited about the chance to do something helping out, and I think it's freakin' great if he could get out there and tote the ball for us. The circumstances rolled just at this time, and he could have four or five games left in him. Maybe that's what we need."
Despite Lynch's time away from the NFL, the Seahawks (11-4) are desperate for help at running back as they prepare for their showdown Sunday night against the San Francisco 49ers (12-3) in a game that will determine the NFC West champion.
Seattle also is without backup running backs C.J. Prosise (arm) and Rashaad Penny (knee), who are both out for the rest of the season.
Free agent Robert Turbin, another former Seattle running back, also is expected to meet with the Seahawks on Monday to discuss a return, a source confirmed to ESPN. NFL Network first reported the possibility of Turbin's return to the Seahawks.
Lynch, 33, rushed for 376 yards and three touchdowns in six games with the Raiders last season. He eclipsed 1,200 yards rushing in four consecutive seasons with the Seahawks from 2011 to 2014 and led the NFL in rushing touchdowns in 2013 and 2014.
"He's had plenty of time to be working and get ready in case something came up, and I'm anxious to see him when we get him here," Carroll said Monday. "There's a lot of history here that's great history. There was nobody that ever amplified the kind of mentality and toughness that we like to play with, so if we get a chance to get the Beast back on the field, we'll see how that works out."
Also Monday, Carroll said he expects Jadeveon Clowney to play against the 49ers after missing the Cardinals game with a core-muscle injury he's been dealing with since Week 10. That was the first meeting against San Francisco and Clowney's best game of the season.
ESPN's Brady Henderson contributed to this report.