"Absolutely," the Pro Bowl receiver said. "Any minute now we're going to put it together. I don't know how many wins it's going to take, but we'll be there at the end."
Heading into Sunday's game against Tennessee, the Dolphins (4-4) trail the Jets and Patriots by two games in the AFC East. Miami ranks last in the conference in points, behind even winless Buffalo, prompting coach Tony Sparano to change quarterbacks this week.
Pennington will take his first snap since a right shoulder injury ended his 2009 season in Game 3. Marshall said he was "maybe a little surprised" by the switch.
"You don't expect things like that," he said. "We all know by now Pennington is more than capable. He led this team a couple of years ago to the playoffs, so there's definitely no drop-off there. I think he'll give our offense a little spark. But Chad Henne is a quarterback who can be an All-Pro. ...
"Henne is one of the most gifted quarterbacks I've been around, and one of the most gifted quarterbacks in the NFL. Pennington has been in the league forever. He has seen a lot of football. We may need that right now."
Marshall said Henne has one of the best arms in the NFL, while Pennington "throws a pretty spiral." But Henne was unable to take full advantage of Marshall, who is on pace for his fourth consecutive 100-catch season but has only one touchdown in his first year with the Dolphins.
A sputtering ground game and dearth of takeaways by the defense have contributed to Miami's modest point total. Those things weren't the quarterback's fault, as offensive coordinator Dan Henning noted.
"Chad Henne didn't miss any tackles. He didn't drop any balls. He didn't miss any blocks," Henning said. "You can't change the whole team. Tony had to make a hard decision, and he made it. I think it sends a message to the team that we're 4-4, and that's not what we want. You take on a guy who might bring a different spark."
Marshall agreed blame for Miami's mediocrity is collective.
"It was a team thing," he said. "We have to do a better job with Pennington back there of making plays and making him look good."
Sparano is counting on Pennington's superior experience, leadership and accuracy to give the offense a boost. The veteran's impact has been apparent in practice this week, Sparano said.
"I always see a spark when Chad's in there," the coach said. "He has a lot of energy. He has done a tremendous job this year -- and it wasn't easy for him, because he wasn't playing -- to bring that kind of energy to practice. What is most interesting is to see people respond to that even though he wasn't the starting quarterback."
The Dolphins began the season confident Henne offered a long-term solution at quarterback. He's 11-10 since becoming the starter last year, throwing 23 interceptions with only 20 touchdown passes.
Henning said the third-year pro still has a bright future.
"There's no reason this guy can't be a good quarterback in this league," Henning said. "He has the tools, he has the work ethic to the nth degree and he's a very tough guy. He's a sensitive guy, but he is a tough guy. He'll come back from this."
Information from The Associated Press contributed to this report.