The phrase Change doesn't happen overnight wasn't coined by Chip Kelly, but he would probably nod in approval to the rest of Mary E. Pearson's axiom that change is molded by people who don't give up.

The coach was asked several times during the last week about changes he might implement in light of the worst offensive performance the Eagles have had under his stewardship, and Kelly's answers each time were relatively the same.

"We're always working on our game plan in terms of what we're trying to do, but I also don't think you just drastically change, and we're going to turn into a run-and-shoot offense and throw the ball a hundred times," Kelly said. "I think we're still going to do what we do."

It has worked many times before, so why change for the sake of change? Kelly's systematic approach to coaching has gotten his teams out of ruts before. Last season, the Eagles went through a similar stretch in which the offense scored only three points in games against the Cowboys and New York Giants.

The situation was more dire than it is now for the 3-1 Eagles, who host the 1-2 Rams on Sunday. They were 3-5, seemingly out of the playoff hunt, and a few players were still unsure about Kelly in his first season. But he stuck to his blueprint, confident that execution was the missing element, and the Eagles trounced the Raiders the following week and won seven of their next eight.

It's why many players said they believe Kelly will steer them through this rough patch.

"The reason he doesn't panic or the reason he doesn't get rattled is because he's a very confident man himself," center Jason Kelce said. "So if the head guy is like that there's obviously a trickle- down effect. It's almost like if the alpha dog's doing it that way, we're confident if he's confident."

There was a moment, however, caught by a Fox TV camera that suggested Kelly didn't have the answers. He was feverishly flipping his play card in the second half, seemingly trying to find a solution to the 49ers defense.

The Eagles had made halftime adjustments in the previous three games that allowed them to stage comebacks. According to guard Todd Herremans, Kelly's scheme allows for more in-game alterations than the Eagles had under former coach Andy Reid.

"I remember when we were in Andy's offense, we would have a certain game plan, and if we went into the game and said, 'Hey, this play will work,' they would be like, 'That's not in the game plan. We don't have it on the call sheet so we can't call it,' " Herremans said.

Kelly said that he "very rarely" calls a play that wasn't practiced during the week and that he never draws up plays during in-game breaks. He has his system, but as Herremans noted, the plays are flexible enough to adapt to the defense.

"Andy and Marty [Mornhinweg] would install their offense and then that would be it," Herremans said. "The adjustments they had would be different routes, stuff that I wouldn't really understand. The way Chip does it is we can tweak certain aspects of the blocking."

An offseason narrative had it that defensive coordinators would catch up to Kelly. Players on both teams last Sunday suggested the 49ers sometimes knew which plays were coming. Kelly said that the limited game plan, because of injuries on the offensive line, may have benefited 49ers defenders.

While Kelly isn't apt to make significant changes from week to week, some expected him to unveil new formations and plays this season after his first full year of studying NFL defenses. The Eagles also added new weapons such as Darren Sproles, Jeremy Maclin, and Jordan Matthews.

The offense has looked much as it did in 2013, however. Losing right tackle Lane Johnson, left guard Evan Mathis, and Kelce may have curtailed Kelly's plans. The Eagles survived the lack of a running game and beat the Redskins two weeks ago, but the 49ers stifled running back LeSean McCoy, too, and quarterback Nick Foles and the passing game couldn't compensate.

McCoy was held to 103 yards on 33 carries for a 3.1-yard average in losses to the Cowboys and Giants last year, but his recent struggles are on another sublevel. He has rushed 29 times for just 39 yards (1.3 avg.) in the last two games.

"I know he likes to run the ball," McCoy said of Kelly. "I'm sure he wants to get things situated. He definitely does. He's more frustrated that we're losing. He's one of those guys that wants to be perfect. I like it like that. I'm with him."

To Kelly, perfection is a balanced offense. The Eagles had the most balanced offense in the NFL last season. Over the course of a season, a successful Kelly offense should have a near even split. But in the first four games, defenses weren't respecting the pass.

"No team is going to let me just do what . . . I want to do, like last year," McCoy said. "They know they can't wait till the game to do it. One-on-one they can't get me. So I respect it because it's a sign of respect. It's like they're not going to let me do it again. I wouldn't. But we'll figure it out."

Kelly honed his system to be adaptable. He said there weren't "Aha!" scheme-altering moments. But he has changed like the seasons, incrementally, and many of the Eagles said they're true believers in Kelly's evolution.

"That's why I said from the very beginning that the stuff he's going to do will revolutionize the NFL," tight end Brent Celek said. "I believe in it and forever will because the guy is constantly evolving. He'll never stay the same. He's constantly trying to get better. He lives this [stuff]."

Asked why he thought the Eagles would rebound, receiver Jeremy Maclin had only four words:

"In Chip we trust."

@Jeff_McLane