Don't get me wrong. I am not saying that yielding Porcello ( and subsequently lavishing him with $20. mil/yr "unproven" ) was the best situation.
I am not a huge fan of Cespedas as you all know. But when he said that he was not likely to return to Boston in 2016 he pretty much punched his ticket out of town. That is on him. The clowns in the FO only played salvage after that.
And, there is no way in hell Cespedas can be compared to Manny.
Manny was a special talent even with his "quirks". At no point in his career has Cespedas shown that he would provide anywhere near the production and even value that Manny did.
Cespedas may be a professional baseball player. But that does not mean that he would have acted professionally while in Boston. That was obvious immediately when he refused or "declined" to play right field upon arrival.
I wish that the Sox had done better homework on the guy. Maybe they could have gotten more or better for 1/2 season of Lester.
In any case, it's milk over the dam at this point. Just more moves that have not worked out, unfortunately.