The Vikings' search for a new offensive coordinator will extend at least one more week, according to General Manager Rick Spielman, who wants to interview "maybe one or two" more candidates.

The Vikings want to interview Eagles quarterbacks coach John DeFilippo after Philadelphia plays in Sunday's Super Bowl at U.S. Bank Stadium, a league source told the Star Tribune. However, the same source believes DeFilippo is leaning toward staying in Philadelphia.

Complicating the hire is the Vikings' uncertainty at quarterback, including Teddy Bridgewater's contract situation.

"Whoever the offensive coordinator is, part of the process is do you blow it up and start from a whole new system?" Spielman said. "Or do you continue to build on what we've built over the past year and a half? So those are the decisions Coach Zim will have to make."

Spielman and coach Mike Zimmer conducted four interviews at Zimmer's Kentucky ranch, which included Vikings quarterbacks coach Kevin Stefanski, former Seahawks and Vikings coordinator Darrell Bevell and, reportedly, Saints assistant coach Dan Campbell and Texans quarterbacks coach Sean Ryan.

The Vikings don't expect to conduct second interviews with candidates before deciding, according to Spielman.

No other changes to the Vikings coaching staff are expected. The new coordinator will help steer the direction at quarterback, where the team's three past starters are all pending free agents in Sam Bradford, Case Keenum and Bridgewater.

"[The coordinator] will have a major part of the decision-making process," Spielman said. "He'll be heavily involved in that."

Bridgewater's contract may "toll" or roll over the final season of his rookie deal into the 2018 season, based on language in the collective bargaining agreement that says a player on the physically unable to perform list "as of the sixth regular season game" could have his contract tolled if he's in the final season of a deal.

Bridgewater was activated off PUP in Week 10. An attempt to toll his contract could open a legal battle between the NFL's Management Council and the players' union to interpret the rule in Bridgewater's case. He backed up Keenum for eight games and played in Week 15.

"He's technically ready to become a free agent," Spielman said, adding of tolling Bridgewater's deal: "If it goes into that area, it's not a Minnesota Viking [decision], it's an NFL and player union [decision] that will have to decide that area."

NFLPA executive director DeMaurice Smith said Thursday he's unsure if the Vikings or the NFL have to initiate the tolling of Bridgewater's contract.

However, the issue at the center of the matter would be whether Bridgewater was physically able to play football as of the sixth regular-season game, Smith said.

"One of the critical issues was whether he was medically cleared or medically able to play," Smith said. "We continue to take a look at that issue. We're staying in touch with his agent."

Bridgewater told reporters Oct. 19 (Week 7) that he "probably could have practiced a while ago, but we wanted to be smart about everything."

He was inactive for both Vikings playoff games behind Bradford, who underwent knee surgery Nov. 7.

"Each day I had to maintain the right mind-set that it's not about me," Bridgewater said.

No matter the direction at quarterback, the Vikings have financial flexibility.

Spielman enters the 2018 offseason with roughly $57 million in salary cap space, based on NFLPA data and a reported increased salary cap of $174 million to $178 million for next season. The official cap for each team won't be set until March.