WASHINGTON (Reuters) - Jeff Sessions, a former attorney general forced out by President Donald Trump, will announce on Thursday he is running next year to regain his old U.S. Senate seat from Alabama, a Republican official familiar with his plans said on Wednesday.

Sessions, 72, a frequent target of Trump’s anger over his decision to recuse himself from the Russia probe, will be trying to reclaim a seat he resigned to join the Trump administration.

His decision to enter the race was first reported by the Associated Press.

Sessions enters a crowded field seeking the Republican nomination to face Democratic Senator Doug Jones in the November 2020 election in a Southern state considered reliably Republican.

Sessions held the seat from 1997 to 2017.

Sessions “wants to get back in the game,” and U.S. Senator Richard Shelby of Alabama will help him raise money, said the Republican source, who spoke on condition of anonymity.

The source said Sessions was the Republican Party’s best chance for a Senate pickup in next year’s election, but it was unclear how Trump would react to the development.

Trump has called his selection of Sessions as attorney general “the biggest mistake” of his presidency.

Sessions was an early and loyal supporter of Trump. But after being publicly ridiculed by the president, Sessions was ousted on Nov. 7, 2018. He was replaced briefly by Matthew Whitaker until William Barr was confirmed to the job in February.

Sessions’ decision to recuse himself from the federal investigation of Russian interference in the 2016 U.S. presidential election paved the way for the appointment of Special Counsel Robert Mueller. Trump has denounced the Mueller probe as a “witch hunt.”