Red Sox Nation may have seen the last of left-handed reliever Hideki Okajima.

According to ESPN, which cited a club source, on Wednesday night the Sox non-tendered the southpaw.

Oki had a 4.50 ERA in 2010 while making $2.8 million — which included $50,000 in performance bonuses. Upon returning to the bullpen in September following a stint on the disabled list with a strained hamstring, Okajima posted a 1.38 ERA and allowed just two runs on nine hits in 13 innings over 15 appearances to finish off his shaky 2010 campaign. Heading into September, Okajima had a 5.73 ERA in his first 41 games.

It has been a steady decline for the Japanese reliever since joining the Sox in 2007. In his first season at Fenway, Okajima was stellar, posting a 2.22 ERA and a .971 WHIP in 66 appearances en route to an All-Star Game nod.

Should Oki be on the move, Boston has a few candidates ready to battle it out for his spot. The Sox acquired lefty Andrew Miller from the Marlins earlier this offseason for Dustin Richardson. Miller has started 59 of his 79 career appearances over five years, but will likely make the transition to full-time reliever with Boston in 2011. Southpaw Felix Doubront, who made 13 appearances (three starts) for the Sox in 2010, is also likely candidate to see more time out of Terry Francona’s pen.