SANTA CLARA, Calif. (AP) Ahmad Brooks realizes how much Vic Fangio had to do with the San Francisco 49ers ranking among the NFL's top defenses during his tenure. The defense regularly stood at the top or among the best at stopping the run.
The franchise's former defensive coordinator will be working on the other side Sunday, one of several familiar faces with the Chicago Bears opposing the Niners (3-8) at Soldier Field as they search for their first road victory following an 0-5 start away from home.
''It's been a big adjustment for the team this year not having him here,'' Brooks said. ''I think we've done a pretty good job.''
Yet Fangio isn't the only one gone from those top 49ers units. Patrick Willis, Chris Borland and Justin Smith retired last offseason, while Aldon Smith was released, signed with the Oakland Raiders and played nine games before being suspended for a year.
Chicago defensive backs coach Ed Donatell served as San Francisco's secondary coach. And Bears offensive coordinator Adam Gase interviewed for San Francisco's head coaching opening that went to Jim Tomsula following the departure of Jim Harbaugh after last season.
''Vic taught us a lot. He was the coach that I had when I was first here,'' defensive lineman Mike Purcell said Thursday. ''It'll be interesting going against him.''
Fangio took the high road this week when discussing what might have been in the Bay Area, where 49ers CEO Jed York decided to promote Tomsula from defensive line coach despite no NFL experience as a coordinator.
When the season ended, linebacker NaVorro Bowman was rooting for Fangio to stay. Eric Mangini replaced him.
''I would like to see Vic Fangio here, whether that's as head coach or DC,'' he said.
When asked on a conference call Wednesday with writers covering the Bears whether Fangio did enough to be considered for the 49ers head coach position, he said: ''I think so. I don't see why not.''
Fangio's current group might not be flashy, yet it hasn't mattered. The Bears (5-6) are making big strides on both sides of the ball.
San Francisco has struggled on third down, going 0 for 9 on conversions in last week's 19-13 home loss to NFC West-leading Arizona and 2 for 11 the previous week at Seattle.
It won't get any easier in a tough environment against a Fangio-led unit.
''They're a sound defense. Schematically, they're on it. They don't make a lot of errors. Their guys are in the right spots. So, it puts it on the quarterback and the guys on offense to execute and be consistent in sustaining drives,'' quarterback Blaine Gabbert said. ''They make you execute 10-, 11-, 12-play drives and that's tough because as a quarterback sometimes you get greedy, but you just have to be content taking what they give you.''
Gase, too, has been leaning on Fangio more this week before facing an offense Fangio knows well - even if it's Gabbert under center now in place of Colin Kaepernick, who was demoted and then underwent surgery on his non-throwing shoulder last week.
49ers offensive coordinator Geep Chryst referenced the ''Vic Report,'' and Chryst has sat alongside Fangio on enough flights to know how he studies.
''He's got no problem referring to himself in the third person there,'' Chryst said, smiling. ''His confidence stems from the fact that he's doing his homework.''
Brooks knows Fangio's legacy lives on inside Levi's Stadium through some of those players he helped develop in recent years.
''He meant a lot to the organization while he was here because when he was here as defensive coordinator we were ranked like top-five every year. So that means a lot, knowing you have a good defense every Sunday,'' Brooks said. ''We emphasized a lot stopping the run while he was here. I think three out of the four years he was here as coordinator we were ranked No. 1 as a rushing defense stopping the run. That right there, that was something we wanted to continue to go forward with into the season, we just haven't held up to that standard.''
AP NFL website: www.pro32.ap.org and www.twitter.com/AP-NFL