Since John Farrell is Boston's manager for the next three years, it's obvious he wanted to come back to the Red Sox. But, before Boston even inquired about him this off-season, Farrell told Toronto Blue Jays general manager Alex Anthopoulos as much (via Scott Lauber):
"As John explained it to me, this was a dream job for him," Anthopoulos said. "It was a once-in-a-lifetime opportunity that he felt very strongly about. We would do what we could, but he also understood that we weren't just going to send him there or give him away or let him out of his contract. That wouldn't have made any sense for us."
Boston did come calling eventually, but apparently, they didn't think Toronto was going to be any more willing to let Farrell out of his contract than they had been a year before:
The on-again, off-again discussions continued for nearly 10 days, during which time Red Sox GM Ben Cherington interviewed four managerial candidates: Dodgers third base coach Tim Wallach, Yankees bench coach Tony Pena, Padres special assistant Brad Ausmus and Orioles third base coach DeMarlo Hale. But one industry source maintained the process wasn't a charade, noting the Blue Jays didn't grant permission for the Red Sox to speak with Farrell until Friday night.
The Red Sox had four candidates lined up, candidates they liked very much for the job. But Farrell was always the preference. Just because you prefer someone doesn't mean anything, though, since Farrell still had to be let go, and that was in Toronto's hands. This was a case of good planning by the Red Sox, and likely the fact they had four options they liked aside from Farrell played well in negotiations. Boston didn't need Farrell, but the Jays might then end up stuck with a manager on a one-year deal who has already explained he would rather work elsewhere.
The fact the Jays wanted a major-league player in exchange for Farrell was a relief to many Red Sox fans (including readers here), who felt that Toronto would attempt to dip into Boston's strong farm system for compensation. Instead, a player who had already lost his starting job, and could have been a bench player had he been retained, was sent over the border in exchange for Boston's new manager. It's likely this was also a relief to Boston, as they get their man, and clear up one roster situation that needed dealing with in the process. All without giving up even a B-level prospect, too.
The whole Lauber piece is worth reading, as the process is detailed from start to finish. Especially for the line where it's made clear Farrell is the only candidate in the last two years (including the last manager, Bobby Valentine) that both the front office and ownership agree on. Given the tumultuous last 13 months or so, that's the kind of thing you like to hear.