Matt Williams is expected to accept an offer to be the third-base coach for the Diamondbacks next season, according to multiple reports.
Williams, who was fired as the Nationals' manager after the past season, played third base for the Diamondbacks from 1998 through 2003, his last season in the majors.
He will replace Andy Green on the Diamondbacks staff. Green was recently named the manager of the San Diego Padres.
Williams bought a small ownership stake in the Diamondbacks after his retirement but has since sold it. He was a member of the team's coaching staff from 2010-13, then was hired as the Nationals' manager in 2014.
The Diamondbacks are also expected to name Garvin Alston to replace Mel Stottlemyre Jr. as bullpen coach. Stottlemyre left the team to become the Seattle Mariners pitching coach.
The official announcement of Williams' and Alston's hirings is expected Wednesday.