Zachary Quinto starred as Dr. Oliver Wolf on “Brilliant Minds” for two seasons on NBC. For the June 3 episode, he stepped behind the camera as well, picking up his first directing credit.

It’s fairly routine for actors, writers or cinematographers on a show to temporarily assume the director’s chair. But it does not sit well with the Directors Guild of America, especially as fewer shows are getting made and fewer directing jobs are available.

The DGA maintains that doing two jobs at once shortchanges the director role while taking a job that could go to a career director.

So, under a tentative agreement reached last week, “affiliated hires” will be allowed to direct no more than two episodes per TV season. For a show with fewer than eight episodes, only one “affiliated hire” will be allowed to moonlight as a director.

The agreement is the product of a compromise with the Alliance of Motion Picture and Television Producers, and is riddled with exceptions and loopholes. It is hard to state how much effect it will have. But to the extent that it is effective, it could limit career opportunities for actors and others who want to transition to directing.

Many veteran TV directors got their start in front of the camera. “Grey’s Anatomy,” for example, has long given episodes to actors who want to direct. Kevin McKidd, who appeared as Owen Hunt, went on to direct 48 episodes — the most of any director on the show. Shondaland has even celebrated the work of actor-directors, highlighting the 13 best “Grey’s” episodes directed by members of the cast.

The DGA has emphasized that the limitation does not apply only to actors. It also covers most other non-directors as well, although a show’s creators — the showrunners or those who write an episode in the first season — are allowed to direct without it counting against the cap.

Noah Wyle, the star of “The Pitt,” directed an episode in the second season. Had the deal been in place, his episode would not have counted toward the two-episode limit because he also wrote two episodes in the first season.

An executive producer or co-executive producer would also not count toward the cap — provided they do no writing or acting on the show. A “producer-director” who has no other role on the show likewise would not count toward the cap.

In a contract summary, the DGA said that the limit is intended to preserve directors’ jobs, but is not meant to constrain opportunities for those with a sincere interest in becoming directors.

“This supports Directors – both established veterans and those in the pipeline – while still allowing those who are serious about directing as a career, even if working in other capacities, to continue building their directing careers,” the summary stated.

The contract language also includes a carve-out for shows where all of the “affiliated hires” are either experienced directors or are hired to direct the entire season. An experienced director would have to have directed either two movies, eight TV episodes (of which at least four episodes came when directing was their sole job), or 10 TV episodes across three shows.

SAG-AFTRA, which represents performers, declined to comment on the DGA deal.

The DGA is also seeking to protect its members’ jobs by extending its jurisdiction overseas. Under current conditions, when a U.S.-based show is filmed abroad, producers are willing to apply DGA terms about 85% of the time. The DGA is looking for more than that. But the AMPTP did not grant an expansion of its jurisdiction.

The AMPTP did agree to issue a bulletin reminding producers not to discriminate against DGA members when hiring for roles overseas. And an existing industrywide body, the Geographic Scope Committee, will meet before the end of the year to continue the discussion about overseas coverage.