The first-year head coach told reporters Monday that the Browns expect to name their starting quarterback by their third preseason game, which takes place Aug. 23 against the St. Louis Rams.
Whether the Browns choose Manziel, a Heisman Trophy-winning rookie, or Hoyer, a six-year veteran and Cleveland-area native, still is a matter of debate.
Pettine told reporters that the Browns have not established an exact deadline for naming a starter, although they would prefer to make a decision soon.
He planned to meet with offensive coordinator Kyle Shanahan and quarterbacks coach Dowell Loggains to discuss the competition between Manziel and Hoyer.
"It's definitely still up in the air," Pettine said, according to the Akron Beacon Journal. "It could be sooner, and that's something we're going to discuss in that meeting. It'll be before the third preseason game. I just don't have a date. I don't know if I'll set a date and kind of paint ourselves into a date, but it will be sooner than the third preseason game."
Pettine discussed a wide range of topics involving Manziel on Monday, asserting that the rookie's off-the-field activity will be " a nonstory" once training camp starts. Pettine also praised Manziel's work ethic this offseason.
"He's been very humble," Pettine said. "He's been great in the meeting rooms. Worked hard -- worked hard in the weight room; one of the best guys in the weight room. Asked the right questions. I think he's ahead of the learning curve."
Pettine also said that he wants to hold a "fair" competition between Manziel and Hoyer, who led Cleveland to two straight wins last season before suffering a season-ending knee injury in his third start.
"We want to make it as open and fair a competition as we can," Pettine said, according to the Beacon Journal. "But you've got to be careful then, too, because you've got a guy that's potentially your starter, and you have supporting-cast issues, whether that's in a preseason game or whether you can control it a little better in practice. Then the issue that I talked about before is kind of finding that sweet spot date" for naming a starter.
Pettine left open the possibility that Hoyer and Manziel could each get a start in the first and second preseason games.
"That's something that hasn't been decided yet," Pettine told ESPN.com on Monday. "That might be something that potentially could come out of the scrimmage [at the University of Akron on Aug. 2]. 'Hey, both are playing well, let's go ahead and let one start the game one start the other.'
"There are a lot of different ways we can approach it, but there will be a lot of thought to it."
The Browns' training camp begins Saturday at the team's training facility in Berea, Ohio.
ESPN.com Browns reporter Pat McManamon contributed to this report.