METAIRIE, La. -- The New Orleans Saints had better be prepared for anything this week as they set to host a 1-6 Tennessee Titans team that made the surprise move to fire head coach Ken Whisenhunt on Tuesday morning.

The Saints (4-4) already had to prepare for the possibility of two different quarterbacks, with rookie Marcus Mariota expected to come back this week from a knee injury and reclaim his starting job from Zach Mettenberger.

Then the Titans dropped the bombshell Tuesday, firing Whisenhunt less than two years into his tenure and replacing him with interim coach Mike Mularkey.

This Sunday, the Saints will try to contain Marcus Mariota, who has completed 64 percent of his passes. Wesley Hitt/Getty Images

The Titans’ offense likely won’t change radically from what they showed during the first five games when Mariota was at the helm. But the Saints would still be wise to expect the unexpected from a desperate team with new leadership in charge.

Could that give Tennessee an emotional jolt? Perhaps. The Miami Dolphins won two straight games last month after replacing head coach Joe Philbin with interim coach Dan Campbell. On the flip side, when the Oakland Raiders fired Dennis Allen after an 0-4 start last year, they continued on to an 0-10 start.

The Saints are familiar with Mularkey, who served as the Atlanta Falcons’ offensive coordinator from 2008-2011 -- though Mularkey won’t necessarily be calling the offensive shots since Jason Michael remains the Titans’ offensive coordinator.

Mariota is the guy the Saints need to focus on most.

The reigning Heisman Trophy winner from Oregon and the second pick in this year’s draft got off to an explosive start this season with four touchdown passes in his debut victory over the Tampa Bay Buccaneers.

That was Mariota’s only NFL victory, but he has been solid in his five starts overall (9 TDs, 5 INTs, 1,239 yards, 64.0 completion percentage, 93.2 passer rating).

Mariota is a threat to run the ball, though he has only 10 rushes for 72 yards this year. His athleticism makes him more dangerous whether he’s running the ball or just moving in the pocket.

“We’ll prepare for both,” Saints coach Sean Payton said of Mariota and Mettenberger on Monday. “I think there are elements that are different [depending on which QB is in the game], not having seen much of their offensive film yet. But I’m sure that there are some things that they might want to do a little bit more of with one than the other. We’ll have to put the tape on and see if we can get a profile.”

The Titans’ offense hasn’t been very good with either quarterback at the helm. They are ranked 31st in the NFL in yards per game (309.9) and points per game (17.9). And they have been especially porous when it comes to pass protection.

Tennessee has allowed an NFL-high four sacks per game this year. Mettenberger was sacked seven times last week in a loss at Houston. Mariota was sacked seven times in a Week 2 loss at Cleveland.

In theory, the Saints should have rookie QB Mariota right where they want him in a hostile environment in the Mercedes-Benz Superdome.

But that was also the case in Week 2, when they allowed Buccaneers rookie Jameis Winston to get way too comfortable in his first NFL road start as Tampa Bay beat the Saints, 26-19, with Winston throwing for 207 yards and one TD with zero interceptions and three sacks.

The Saints have improved since then, winning their past three home games.