MOBILE, Ala. – Coach Kyle Shanahan has filled out his defensive staff, but he is still contemplating the moves he must make to finalize the list of 49ers offensive assistants.

“Even though it was unfortunate to lose two good coaches on offense, I do look at it as an opportunity to see if we can improve in any other areas,” Shanahan said Tuesday at the Senior Bowl.

“(But) it’s going to be tough to get guys specifically who are better than those two.”

Former quarterbacks coach Rich Scangarello is the new offensive coordinator of the Denver Broncos under coach Vic Fangio. And former assistant offensive line coach Adam Stenavich is the new Green Bay Packers offensive line coach under first-year coach Matt LaFleur.

Initially, the 49ers denied the Broncos permission to speak with Scangarello. The 49ers denied passing game coordinator Mike LaFleur and run game coordinator Mike McDaniel opportunities to be non-playing calling offensive coordinators of other teams.

“I needed more time to talk about it,” Shanahan said of immediately filing the paperwork to deny the Broncos permission to interview Scangarello.

“The initial reaction (was) I don’t want to lose good coaches, at all, and you don’t have to. But it’s very tough to keep a coach back when he’s getting a huge promotion. It’s a tough position that we’re in because I want to do right by people, always. But my No. 1 job is to do what’s best for the 49ers. That’s what you got to always think about, and losing good coaches is not what’s best for the 49ers.”

Shanahan said he spoke with Fangio and Broncos general manager John Elway to be assured that Scangarello had a strong chance to get the job and his role would constitute a promotion. The 49ers informed the Broncos they could interview Scangarello, and he was hired last week.

Teams are allowed to deny assistant coaches under contract for any job that is not an opportunity to be a head coach.

The 49ers dened LaFleur opportunities with Green Bay and Minnesota. Although Mike LaFleur would have worked for his brother with the Packers, Shanahan said it was more difficult to deny Minnesota because it was a better job. Matt LaFleur will call the plays in Green Bay.

The club denied Arizona from speaking with McDaniel. New Cardinals coach Kliff Kingsbury will call the plays.

“It wasn’t a promotion,” Shanahan said of those jobs. “Mike and Mike, I gave them the coordinator title before the year started. That’s what they do for us. They are under contract, so that one was a very easy one for me.

“I listen to every one. I would not feel guilty or bad. I know the situation they’re in here and what we’ve done together for a long time. I know how important they are here and what they do here. Why would I let them go do that for someone else?”

Mike LaFleur and McDaniel will be presented with contracts for one-year extensions in the offseason. If the coaches sign the extensions, the 49ers again would have the opportunity to deny them the possibility of assistant coaching positions with other teams next offseason.

In the meantime, LaFleur and McDaniel will run the offense this week and share in the play-calling for the South squad at the Senior Bowl. Both assistants are also candidate to replace Scangarello as the team’s quarterbacks coach. Shanahan noted the 49ers have two strong in-house candidates.

He also has the option of considering other coaches from outside the curent staff.

The 49ers have made two changes to their defensive staff. Former Denver defensive coordiantor Joe Woods replaces Jeff Hafley, who takes over as Ohio State's co-defensive coordinator. Kris Kocurek takes over as defensive line coach. The 49ers fired Jeff Zgonina when Kocurek became available after the Miami Dolphins fired their coaching staff.

Neither Woods nor Kocurek are in Mobile this week. That was a perk Shanahan said he gave them to help convince them to sign with the 49ers.

“That was part of my recruiting for them,” Shanahan said. "I threw that out there before they said yes. If they’d said yes (immediately), I wouldn’t have thrown that out there."