"This is my move, without question," Ryan said, adding that he met Friday morning with owners Terry and Kim Pegula. The coach said they were supportive of the call to part ways with Roman, the NFL's highest-paid offensive coordinator.
Roman, 44, was hired shortly after the Pegulas named Ryan their head coach in January 2015. Roman previously served as the San Francisco 49ers' offensive coordinator from 2011 to '14.
The Bills replaced Roman with assistant head coach/running backs coach Anthony Lynn. The 47-year-old served as Ryan's running backs coach with the New York Jets from 2009 to '14, before joining Ryan in Buffalo last season.
"I think we need a change," Ryan said Friday. "I think we have a lot of talent on offense. I believe that. I believe we're going to do what we can to put the ball in our playmakers' hands. I think Anthony will do that."
The change at coordinator comes less than 24 hours after the Bills fell to 0-2 with Thursday night's 37-31 loss to the Jets. Buffalo's offense gained 393 total yards in the game, bouncing back from a 160-yard outing in a season-opening, 13-7 loss to the Baltimore Ravens.
Meanwhile, Buffalo's defense allowed 493 total yards against the Jets' offense, including 374 passing yards from Ryan Fitzpatrick, leading Ryan to say after the game he "never expected" the offensive success of the Jets.
On Friday, when asked why Roman was fired despite the defense's struggles Thursday, Ryan responded, "I understand [the question]. Certainly the defense has to improve. There's no doubt about that. But this, I think if it was appropriate to do something else, then I would have. To me, I thought this was the move that I felt that we needed to make to help our team moving forward."
Ryan does not expect drastic changes to the Bills' offensive playbook or terminology because the change at coordinator is happening during the regular season. Compounding matters for Lynn will be the Arizona Cardinals' stout defense in Week 3.
"I think, obviously, it's going to be very challenging," Ryan said. "There's no question about it. [But] I think our players will be excited about Anthony running the show."
Ryan said he hopes quarterback Tyrod Taylorwill benefit from the offensive coordinator shakeup. Taylorwent 8-6 as a first-time starter last season before the Bills extended his contract this summer for up to five additional seasons.
"I believe [Taylor's] ability as a drop-back quarterback, as a quarterback that's athletic, we can do things with," Ryan said. "I think he's a rare talent. We have to do things that I think will showcase those abilities a little bit. He has some unique abilities."
Ryan also wants to see top receiver Sammy Watkinscatch the ball more often. Watkins has battled foot soreness early this season because of surgery, but he has recorded six catches for 63 yards and no touchdowns through two games.
"I think Sammy Watkins is a rare talent," Ryan said. "I've had to defend against him, and I know how difficult that was. I thought at the end of last year, we did a great job of getting him the football. I expect that we're going to try to get him the football more and more."