"Be careful what you wish for," Fuller told the fans who chanted for then-backup Kelly Holcomb to replace the former No. 1 overall pick.
According to Fuller, who signed with the Baltimore Ravens in the offseason after four years as a cornerback with the Browns, "the fans just don't understand."
"I'm a Couch fan and I'm a Holcomb fan, but this is the reality of it. When you are not starting every play, every down, every day, it is a totally different ball game."
Fuller believes Holcomb is beginning to learn that life as an NFL starting quarterback isn't all that easy.
"When you go home at night now, you sleep with the pressure that ‘I"m the starter. I can't make a mistake," said Fuller. "When he was second string, he was thinking ‘if I can just make some plays, maybe I can pressure for the starting job ... He didn't feel any pressure to perform."
Playing free and easy in the regular season filling in for an injured Couch, Holcomb posted some eye-opening numbers against some average defenses last year. He then won the right to challenge for the starting job in training camp by closing the season with a 400-yard performance against the Pittsburgh Steelers in the first round of the playoffs.
"Kelly Holcomb has played two games since," said Fuller. "Those stats don't look like they used to look, do they?"
And why is that? According to Fuller, Holcomb simply isn't an unknown quantity anymore.
"People respect a quarterback's ability after throwing for 400-some yards in a playoff game," said Fuller. "It's just like a hotshot rookie coming in. The next year, he gets gameplanned for."
After watching Holcomb struggle against the Indianapolis Colts' two-deep zone in last week's season opener, Fuller and the Ravens found a model of what works against Holcomb.
The two-deep zone takes away the seam route and the deep middle of the field, frustrating the aggressive-minded Holcomb
"This is a copycat league," said Holcomb. "Everybody saw what we did in the preseason. They are not going to allow you to get big plays. When they do allow you to make big plays, you have to make them, and we didn't make them."
Holcomb completed less than 50-percent of his passes (17-of-37) for just 147 yards against the Ravens, and was intercepted twice by Ravens Ed Reed. He claimed that Ravens' linebacker Ray Lewis hurt his completion percentage by dislodging the ball from receivers hands, but by consistently floating balls to his targets, Holcomb often gave Lewis the opportunity to time up his big hits.
Sunday's performance shows that "Couch wasn't the problem," said Fuller.
"How can Couch be the problem? He was there when that franchise started at zero ... Nobody went crazy on Dennis Northcutt and it took him two years to kick in ... Now my man Couch doesn't look so bad, sitting on the sideline with $6 million. It wasn't Couch."