With speculation surrounding why Mike Nolan decided to leave the Broncos for a lateral move to become the Dolphins’ defensive coordinator, here’s some clarity from what I’ve learned after speaking to sources close to the situation:

• There is no acrimony between Nolan and Broncos coach Josh McDaniels. The Dolphins sent the Broncos a written request to interview Nolan. McDaniels approached Nolan with the request and, in a nutshell, asked him if he’d rather be in Miami or Denver. Nolan said he would like to interview with the Dolphins. McDaniels then granted Nolan permission and wished him well.

• The Broncos have allowed their assistants to interview for jobs with other teams this offseason, taking the position that if a coach has an opportunity for a promotion, it wouldn’t stand in the way. That it did the same for Nolan to make a lateral move was somewhat interesting.

• Possibly factoring into Nolan’s decision, his contract with the Broncos supposedly was set to expire after next season, as will a lot of the team’s assistant coaches’ deals. With the possibility of a work stoppage, Nolan foresaw being able to negotiate a contract that would pay him through a lockout with the Dolphins, should the NFL and the NFL Players Association not be able to finalize a labor deal before the 2011 season.

• With a deal coming together so quickly with the Dolphins –- one day after Nolan split from Denver –- parameters of a deal had to have been in place before or shortly after he left the Broncos.