A person familiar with the Bills' search told The Associated Press that the team has contacted the former Denver Broncos' coach. The person spoke on the condition of anonymity because the Bills are not discussing the search.
Shanahan has been out of football since the Broncos fired him at the end of last season. A message left at his Denver office was not returned.
He went 146-91 in 14 seasons in Denver, including the playoffs. But the Broncos struggled in his final three seasons, going 24-24, including an 8-8 finish last year in which they missed the playoffs after losing their final three games.
Shanahan was fired with the Broncos owing him about $20 million over the final three years of his contract. The Bills would have to at least match what Shanahan's owed if they intend to make a competitive offer.
That isn't considered a concern after Bills owner Ralph Wilson told the AP last week that he was prepared to offer a lucrative contract to land a high-profile coach.
Wilson is eager to turn around a franchise that's in jeopardy of missing the playoffs for a 10th straight season. It's a stretch in which the team has enjoyed one winning season -- a 9-7 finish in 2004 -- and is now on its fifth coach.
Bills defensive coordinator Perry Fewell was promoted to interim coach when Dick Jauron was fired last week.
Fewell is also a candidate for the job and will be judged by how the team performs in its final seven games. The Bills (3-7) lost 18-15 at Jacksonville in Fewell's debut last weekend, and host Miami (5-5) on Sunday.
Despite the loss, the Bills' sputtering offense produced 343 yards, the most since generating 438 in a 33-20 win over Tampa Bay in Week 2. And their porous and injury-depleted defense limited the Jaguars to 102 yards rushing, the fewest in eight games.
Wilson has said he's prepared to revamp the entire football operation in a review that's expected to begin immediately at the end of the season.
The Bills are barred from interviewing potential coaching candidates currently employed by other teams until their seasons end. But there are several high-profile former coaches currently out of work.
That group includes Bill Cowher, Marty Schottenheimer and Mike Holmgren, who has expressed interest in working for the struggling Cleveland Browns.
Several media outlets, including ESPN and The Buffalo News, have cited sources in reporting that Cowher is not interested in interviewing for the Bills job at this time. Schottenheimer, a former linebacker who played four seasons with the Bills in the 1960s, has been out of football since being fired by San Diego in February 2007.