After weeks of speculation about his fate, “Law & Order” star Jesse L. Martin has agreed to return next season for at least 13 segs of the long-running show.In advance of May’s last-minute deal to save the show, there had been word that Martin would be leaving whether or not it was renewed. Ultimately, however, Martin and his team were able to work out a compromise with “L&O” creator Dick Wolf. While Martin is signed on for only 13 segs, there’s a provision for him to do more. He’s played Det. Green on the show since 1999. Deal to bring back Martin, even in a diminished role, comes after a slew of cast changes on “Law & Order.” Fred Thompson is ankling for a likely presidential bid, while Milena Govich is out after just a year on the series.