I've never heard of him. You guys?
A left-handed Otsuka? Better?

The Red Sox should soon announce the signing of left-hander Hideki Okajima, likely to a two-year deal.
The soon-to-be 31-year-old Okajima will likely be the top lefty in the Boston pen. His plus curveball helped him to a 2.14 ERA and a 63/14 K/BB ratio in 54 2/3 IP for the Nippon Ham Fighters last season, though it was something of a career year. He might be very good until the league begins to figure him out, at which time he could settle in as a reasonable specialist.
Source: Boston Herald