Smith (shoulder) was reinstated from the 60-day disabled list Thursday and elected to become a free agent.
Smith missed the majority of the 2018 campaign after undergoing shoulder surgery in June. While he's shown promise when healthy, posting a career 2.21 ERA, 1.06 WHIP and 11.4 K/9 across parts of five major-league seasons (102 innings), injuries have limited the right-hander to just 23.2 innings with the Red Sox since the start of 2015.