Martinez, who joins former catcher Jason Varitek in that capacity, said he plans to spend a lot of time helping to develop players and collaborating with team brass.
"I've been away long enough now," Martinez said Thursday. "I spent time with my family, and now the situation is right. I think they need people like me that could probably relate to the players, relate to the front office, have the good communication and the interest that they need right now. I think the players still see me as a player and they can naturally communicate with me. I'm also a veteran, a real old veteran, and I think I can offer some advice how to handle different situations."
In particular, Martinez will spend time mentoring young pitchers.
"I love to teach. I love to deal with the players," he said. "I have a very good relationship with the players and I'm also fun. I like to have fun and I think they need a little bit of that in the clubhouse."
Though he said a comeback was out of the question -- "Don't even think about me coming back," he said -- he's looking forward to getting his "nose dirty."
"I miss the field," Martinez said. "Once I get on the field, I'm going to get involved and get going. I like the field. I like the feel of the sun, sweating on the field, and hopefully some of the knowledge I have I'll be able to communicate to someone and have someone take advantage of it."
Cherington said Thursday morning that both Martinez and Varitek participated in organizational meetings that took place in Boston the past few days.
"I had an impression of him across the field, but to be around him in these meetings, the life and the confidence that he has that are genuine, part of his personality, that's infectious," manager John Farrell said. "That rubs off on people, and I think when you have that type of ability to tap into by others around him, those players will be able to pull some pieces of information, or experiences that should help them individually."
Martinez spent seven seasons in Boston (1998-2004), winning two of his three Cy Young Awards and a World Series ring during his time with the Red Sox. He went 117-37 (a franchise-best .760 winning percentage) with a 2.52 ERA in his seven seasons with the Red Sox, leading the league in ERA four times in that span.
Former Red Sox skipper Terry Francona, who coached Pedro on the 2004 title team, said he thought bringing Pedro back was a great idea.
"It's interesting. It probably means he has to be on time now," Francona said with a laugh. "I'll tell you what, if you want to get input on how to pitch, you can't go to a smarter guy. I think it's great. I think it's a good fit. Once you start bringing guys back like Varitek and Pedro -- they are the Red Sox. I think it's terrific."
Martinez left the Red Sox after the 2004 season to sign with the Mets, for whom he pitched four more seasons. His final season in the majors was 2009 with the Phillies.
"I am thrilled to be returning to this organization and to the city I love," Martinez said in a statement. "Ben Cherington's meetings this week have been outstanding. It is an honor to be back with the Red Sox and help in any way I can. I am grateful to our leaders; I believe in them, and I thank them for allowing me to return to the field and help us win again. My heart will always live in Boston."