McGehee became a free agent in November and after a month of evaluating his options, the third basemen decided to play professional baseball in Japan. The 34-year-old batted .198 and .227 respectively over the past two major league seasons and so would likely not be a valuable fantasy asset even if he remained in the MLB.
Peterson began the season at the Double-A level last season, but he ultimately got his first extended look at Triple-A and hit .253 with eight home runs in 46 games there. The 24-year-old was added to the 40-man roster over the offseason so he may get a chance in the majors at some point in 2017, but at this point it looks like he'll get the chance for regular at-bats in the minors to start out the year.
Duffy battled soreness in his Achilles/heel area throughout much of the season and ultimately underwent surgery in early September. He's been working through some atrophy since shedding his walking boot, but the Rays seem optimistic that Duffy will be ready for spring training. Entering his age-26 season, Duffy projects as the primary shortstop if indeed healthy.
A fifth-round pick in 2008, he broke through to the majors briefly with the Cardinals in 2013 but has been stuck down at Triple-A ever since. Curtis has routinely posted high on-base percentages, upping his mark to .404 with the Reds' Louisville affiliate in 2016. However, he does not have the other tools necessary to take really capitalize on the strong approach.
The 21-year-old put bat to ball with great consistency in 2016, striking out just 72 times in 570 plate appearances between High-A Tampa and Double-A Trenton (12.6 percent). He's also got some developing power and a great arm at third base, so while Andujar likely needs more seasoning, he could get a look in New York before the end of 2017.
Peterson got off to a hot start with Triple-A Tacoma but cooled down enough that he finished with a .253/.307/.438 line in 192 plate appearances. He should figure into the Mariners depth at the corner infield positions heading into 2017.
Shaffer has a career .213/.310/.410 line in limited major league action between two seasons and figures to occupy a depth role in the corner positions with Seattle. He also took a large step back this season with Triple-A Durham, going from a .937 OPS in 2015 to .695 in 2016. He'll need to bounce back before he can be reasonably considered for the majors.
Abraham notes in his report that Marrero may not be in Boston's organization by the time spring training rolls around, as there is really no room for him despite the fact that he is essentially big league ready. As a glove-first infielder with a below average hit tool, he has little appeal in fantasy regardless of which organization he is in.
This was expected, as Moncada struggled to hit offspeed pitches and breaking balls in the upper levels of the minors and in the majors last season. Despite those struggles, Moncada will enter 2017 as the top prospect in the game for dynasty league purposes, as he is just 21 and still offers superstar level tools. A minor thumb injury cut short his run in the Arizona Fall League, but he will be good to go for the start of spring training. Travis Shaw, Pablo Sandoval and Brock Holt all project to make the 25-man roster out of spring training as options at third base, so the Red Sox can afford to be patient with Moncada. However, once he proves himself capable of handling a steady diet of offspeed pitches at Triple-A, the Red Sox will likely promote him as he would then profile as the organization's best option at the hot corner.
According to Greg Johns of MLB.com, the A's will be receiving right-hander Paul Blackburn in return. Valencia enjoyed a fine offensive season in 2016, batting .287/.346/.446 with 17 homers and 72 runs scored, but he injured Billy Butler in a fight in August and there were rumors that the A's might just release him outright. With the Mariners (his seventh MLB team), Valencia seems primed to take over as the primary option in right field with Kyle Seager locked in at third.