The club announced Monday afternoon that Farrell will be introduced at a news conference at Fenway Park on Tuesday at 12 p.m. ET. The news conference will be held at the State Street Pavilion.
The Sox and Farrell came to an agreement over the weekend that was announced Sunday, with Farrell receiving a three-year contract extension through the 2015 season.
"I'm extremely excited to be returning to the Red Sox and to Boston," Farrell said in a team statement. "I love this organization. It's a great franchise in a special city and region, with great fans, and we want nothing more than to reward their faith in us."
Farrell served as the club's pitching coach from 2007 to 2010.