Sportwereld suggests that the Italian, who has been with Katusha since 2011, has agreed to join the new team where friend and former teammate Paolo Bettini is the manager.
The 37-year-old has won stages Giro d'Italia and Vuelta a Espana including a stint in the maglia rosa in 2012.
Paolini was reportedly offered a contract extension by Katusha which he turned down. Alexander Kristoff is also yet to commit to the team from 2015 onwards.
Bettini has apparently been in contact with numerous riders even if Team Alonso has yet to reveal its formal structure and sponsor.
Peter Sagan is apparently at the top of his shopping list, with Edvald Baosson Hagen, Rinaldo Nocentini and even Tony Martin other possible big-name possibilities. Bettini and Alonso have said they will only target riders who are out of contract this year.
"We're busy working because January 1st is getting close. We're working on what is a great project. I'm discovering more about it every day," Bettini said at Tirreno-Adriatico.
"We're working to build a great team and we'll see the results at the end of 2015. We're convinced you can win big races with new riders.
"I can't say much more. It'll be Fernando who'll do the talking. I've got to focus on getting the work done. He'll give more details when it’s the right moment."
Bettini said an announcement would be made "revealed before the big Classics" but no announcement was made before the Spring Classics.