Jon Morosi, in a series of tweets of greater resolution, has reported that the Boston Red Sox and the Toronto Blue Jays will be completing a trade shortly involving one player from each team, that the player going to the Jays was a Major Leaguer in 2012, and that the Jays will be getting a non-Will Middlebrooks infielder.
WEEI's Rob Bradford has reported that the Blue Jays will receive 31-year old Mike Aviles from the Red Sox.
I would be surprised if the Blue Jays send anything more than an organizational roster filler to the Red Sox.
UPDATE: According to Sportsnet Radio the Fan 590, Bob Elliott of the Toronto Sun has reported that Adam Lind may be the Blue Jays player to go to the Red Sox in the trade.