Winchester native Matt Long begins a guest-starring stint on the ABC medical drama Private Practice on Tuesday, playing a new doctor, Dr. James Peterson. But on Monday, ABC Entertainment spokeswoman Alison Rou said the Grey's Anatomy spinoff will end this season after 13 episodes, most likely in January.

Series star Kate Walsh had previously announced that she would be leaving after 13 episodes.

This is its sixth season on the air. After being paired on ABC's schedule with Grey's Anatomy on Thursday nights, Private Practice moved last spring to Tuesdays.

Private Practice had 6 million viewers last week, ranking it No. 51 in Nielsen's weekly listing of the most popular programs.

Long, 32, is probably best known for his lead role in the 2004-05 drama Jack and Bobby on The WB. Most recently, he appeared in several episodes of Mad Men and the short-lived lawyer drama The Deep End. He also was cast in Private Practice creator Shonda Rhimes' Gilded Lilys, a period drama that didn't get picked up at ABC this season, TVGuide.com reported.

Private Practice airs at 10 p.m. Tuesday on ABC.