FOX Sports' Ken Rosenthal reports that the Mariners are now the fourth team in the proposed four-team deal with the Rangers, Diamondbacks and Indians.
The Rangers, D'Backs and Indians have been the common three clubs in the deal, but the fourth team has varied, with the Rays and Royals also getting involved in the discussions. Rosenthal says the Mariners are "unsure of whether to push forward with the deal," and "amount to the biggest roadblock." Rangers general manager Jon Daniels is spearheading the deal as he, according to Rosenthal, "feverishly" tries to land Justin Upton. But, as is the case with all proposed multi-team trades, there are tons of hurdles to jump, and Rosenthal says, "barring a major shift," it "appears unlikely to happen."