From the Globe:
The Sox were prepared to let Ramirez stay in the lineup and let the option vest if his production warranted it. But after he went 0 for 4 with three strikeouts Thursday, he is now hitting .254/.313/.395 for the season, with a .708 OPS that ranks 30th among 44 first basemen with at least 100 plate appearances.
Yet while Cora continued to pen Ramirez into the lineup, the production cratered this month. Starting with an 0-for-6 game May 1 and continuing through the 0-for-4 night Thursday that extended his hitless stretch to five games (0 for 20), Ramirez struggled to a .163/.200/.300 line this month while seeing his ground-ball rate soar (59 percent of balls in play in May).
The poor numbers aren’t isolated. They represent a step down from his 2017 struggles (.242/.320/.429), and likewise hearken to his 2015 season (.249/.291/.426). Over a two-season period beginning last year, Ramirez ranks in the bottom five among big league first basemen in Wins Above Replacement as calculated by Fangraphs.
In contrast to Jackie Bradley Jr., another Red Sox player who has been in a tailspin this month but whose glove has kept him in the lineup, Ramirez offered negative defensive value at first base relative to former Gold Glover Mitch Moreland.
Yet the Sox were willing to take that risk rather than part with another player from the big league roster — whether by trading Blake Swihart, optioning Bradley or Brock Holt to Triple A, or placing Eduardo Nunez on the disabled list — for a few reasons.
First, Ramirez is limited to first base and designated hitter. Whereas Swihart (catcher, first, third, left), Holt (every position except catcher), and Nunez (third, short, second) all give the Red Sox depth options at a number of positions, Ramirez plays only a position where Moreland looks like the superior two-way option.
Swihart has theoretical upside that the Sox have been unable to explore, in part because he has been behind multiple players at every position he can play. The departure of Ramirez might open more playing time for Swihart at first, and it should maximize the roster flexibility.
Moreover, had the Sox parted with Swihart, they would have left themselves in a vulnerable position with their catching depth should either Sandy Leon or Christian Vazquez suffer an injury.
Furthermore, an unknown loomed about how Ramirez might respond if reduced to a part-time role that would jeopardize next season’s earnings. He repeatedly said that he wasn’t concerned about the $22 million vesting option, and that his sole focus was the team’s performance, but in designating him, the Red Sox won’t have to test that proposition.