The two coached together with the Baltimore Ravens from 2006-07, when Ryan was defensive coordinator and Roman was an offensive assistant.
The Bills reportedly offered Ryan the head coaching job on Saturday night, and he is expected to accept.
The 49ers' coaching staff is undergoing a significant makeover after head coach Jim Harbaugh elected to return to his alma mater, Michigan. His staff came under fire after San Francisco went 8-8 in 2014 after three straight seasons with at least 11 wins. The offense ranked 25th in scoring and 20th in total offense, making Roman a popular target for the ire of 49ers fans.
Harbaugh brought Roman with him from Stanford when he accepted the 49ers' heading coaching job in 2011. Roman was a tight ends/offensive tackles coach at Stanford from 2009-10.
Roman would be the first coach to fall in place for Ryan's staff in Buffalo. According to NJ.com, it remains unclear which assistants Ryan will take from his New York Jets staff. The Jets fired Ryan last month after six seasons. The Bills are believed to be interested in retaining defensive coordinator Jim Schwartz.
Buffalo went 9-7 last season, but has not made the postseason since 1999. Head coach Doug Marrone opted out of his contract shortly after the season ended.
- Mike Fiammetta