The Red Sox need some space on their 40-man roster in order to bring in new players and protect some of their prospects from the Rule 5 draft. They got a little bit of help in that regard on Monday, when infielders Carlos Rivero and Jonathan Herrera exited the organization in moves announced by the Red Sox on Twitter. Rivero was claimed by the Mariners off of waivers, while Herrera was sent to Triple-A Pawtucket and elected to become a free agent instead.
Neither of these moves comes as a shock -- back in late-September, they were both on the list of Red Sox we could expect to lose their roster spot this offseason. Rivero will be 27 next year and is a depth piece for the minors, while Herrera was around in 2014 primarily to give the Red Sox some extra insurance at shortstop after Stephen Drew left as a free agent and Xander Bogaerts had no backup in place. With Deven Marrero at Triple-A, Brock Holt likely on the big-league roster in an emergency, and Mookie Betts around in an even more significant emergency, there was less need for him to take up one of the precious 40-man spots.
The Red Sox have now opened a total of four spots on the 40-man roster since the 2014 season officially ended. Burke Badenhop and David Ross are free agents, Craig Breslow's option was declined, and now Herrera and Rivero have departed, but Shane Victorino was activated from the 60-day disabled list and gobbled up the fifth of those spots. As the Sox could use up all four of those spots just on the Rule 5 protection of Blake Swihart, Eduardo Rodriguez, Sean Coyle, and (maybe) Travis Shaw alone, there are likely more 40-man-related transactions to come in the next few weeks.