"That's a positive thing," coach Mike Pettine said Monday. "Johnny's made a lot of progress in the right direction. Still a lot of things to get cleaned up, but we certainly feel like the arrow is up."
Josh McCown remains in the NFL concussion protocol, though Pettine said he will be examined and could be cleared on Tuesday to return to practice Wednesday.
Pettine said he would get together Monday night with offensive coordinator John DeFilippo and quarterbacks coach Kevin O'Connell about the "what if" regarding who should start the next game against Oakland.
Pettine said he will balance the way Manziel played in completing two big passes to Travis Benjamin in a 28-14 win against the reality that McCown was the team's unquestioned starter through training camp and the first two games of the season.
"We're going to put it all on the table and talk about it and we'll see where it takes us," Pettine said. "As I already mentioned, to me it's a positive conversation because you have a young quarterback that's been through a lot that has gone out and led his team to a win.
"I'm proud of him, because if you would have said back early in the offseason if this was going to happen I think a lot of people would have said it's a pretty slim chance."
McCown started the opener, but left late in the first quarter when he was diagnosed with a concussion after he was hit as he tried to dive into the end zone. The Browns expected him to be cleared to face Tennessee, but he wasn't, so the team started Manziel.
Manziel completed 8-of-15 passes for 172 yards and touchdowns to Benjamin of 60 and 50 yards.
"Quarterback play from A to Z, [Manziel's] improved in all areas, in our mind," Pettine said.
The team will not make a decision based on seeing what Manziel can do. It will decide the starter based on who gives the team its best chance to win, Pettine said.
"We're tasked with winning football games, and the decisions we make are what gives us the best opportunity to win this Sunday," Pettine said. "I know that on the outside that those things get brought into it.
"We've already seen circumstances have come about him for us to get an evaluation of [Manziel]. We're not going to use a season and look at it that way, say, 'Hey we need to know.' We think over the natural course of events that we'll find out."