"A source familiar with the matter told Fox News on Thursday that Whitaker met with Justice Department ethics officials this week, who told him he was not precluded from overseeing Mueller’s investigation into Russian meddling and potential collusion with Trump campaign associates during the 2016 presidential election."
https://www.foxnews.com/politics/acting-ag-matthew-whitaker-cleared-to-oversee-trump-russia-investigation-source-says
It looks like Whitaker has overcome some internal hurdles that were put in his way.