San Francisco 49ers defensive line coach Jeff Zgonina won't be returning to the team in 2019, according to a report from Alex Marvez of SiriusXM NFL Radio.

While Marvez didn't specify whether Zgonina is leaving the team of his own choosing or not, the San Francisco Chronicle later confirmed that he was fired.

Head coach Kyle Shanahan and the 49ers have already blocked requests by several teams to interview members of his staff, including wide receivers/passing game coordinator Mike LaFleur, run-game coordinator Mike McDaniel, and quarterbacks coach Rich Scangarello.

The 49ers recently fired head strength and conditioning coach Ray Wright and long-time head athletic trainer Jeff Ferguson.

Shanahan told reporters on December 31 that he likes his current staff and wants to keep it together.

"I'm not going to ever say that everyone is just totally safe forever," Shanahan said. "But, what I can say is I think our staff is a very good staff and I like what our guys are, and where they can be, and it's the staff I want to hold onto."

Zgonina played 17 years in the NFL as a defensive tackle and was part of the St. Louis Rams team that won Super Bowl XXXIV in 2000. He also played for the Pittsburgh Steelers, Carolina Panthers, Atlanta Falcons, Indianapolis Colts, Miami Dolphins, and Houston Texans. During his time as a player, Zgonina had 448 tackles, 26 sacks, and 13 forced fumbles. His best season was in 2004 with the Miami Dolphins, when he had 63 tackles and five sacks.

Zgonina spent the past two seasons with San Francisco. Third-year defensive tackle DeForest Buckner produced a career-high 12 sacks in 2018 but the group as a whole registered just 37 combined sacks, which was tied for No. 22 in the league.

Zgonina entered coaching in 2013 as an assistant defensive line coach with the Texans and then joined the Giants in 2016 before joining Shanahan in San Francisco.