Okajima, 35, is 16-8 with a 3.06 ERA in 254 career relief appearances with the Red Sox. He struggled for much of 2010. But after spending time on the disabled list in August with a hamstring injury, Okajima returned to allow only two earned runs in his final 13 innings.
Okajima, who earned $2.75 million last season, became a free agent when the Red Sox declined to tender him a contract in early December. He is expected to compete for a bullpen job with fellow lefties Rich Hill, Andrew Miller, Felix Doubront and Lenny DiNardo in spring training.
Jerry Crasnick is a senior writer for ESPN.com.