The Boston Red Sox had a few moves to make to get the 40-man roster into compliance by Monday's deadline.

One move Boston made that didn't shock was designating righty Zack Kelly for assignment. He missed a chunk of the 2026 season due to injury. Plus, he only pitched in 17 games in the majors in general in 2026 as he spent time down in Triple-A. The Kelly move didn't shock. But what decision that did come as a surprise was Boston's decision to designate lefty Eduardo Rivera for assignment.

The Red Sox Surprised

Rivera is just 23 years old and he made his big league debut in 2026. Rivera made four total appearances up in the majors, including three starts, and had a 6.30 ERA. He was significantly better down in Triple-A, though. He had a 2.96 ERA in 24 appearances, including three starts, across 45 2/3 innings pitched. Rivera also made two appearances in Double-A and had a 0.90 ERA.

It was known that the Red Sox had to make moves, but Rivera is young and has great size. He's listed at 6'7'' and 237 pounds. His advanced metrics were good and his fastball flirts with triple digits. That's a guy you should want to try to continue to develop. But the Red Sox designated him for assignment on Monday. It doesn't guarantee he won't stay in the organization.

If he goes unclaimed, he can be outrighted down to the minors if Boston sees fit. But the decision is a bit surprising, especially when you take into account the fact that 27-year-old Raymond Burgos is still on the 40-man roster. He arguably would've made more sense to DFA at this point.

Burgos is 27 years old and arguably would've been more unlikely to be claimed off waivers than the 23-year-old Rivera. At the end of the day, roster decisions aren't always going to be easy. Boston had a handful to make right away because of all of the guys the club had to reinstate from the 60-day Injured List.

Now, the offseason is really in full swing. Trades can be made — which Boston has already taken advantage of — and free agents can start to sign. The Red Sox have been active already and there is plenty more to come. This is already one surprising decision made by Boston and it likely won't be the last.