Joe Flacco's second NFL season has been more struggle than coronation, more roller-coaster ride than straight-line ascension.

Flacco ended the Ravens' agonizing search for a franchise quarterback in 2008. In 2009, he was under scrutiny for costly interceptions, a rash of sacks, his failure to pick up blitzes and a reluctance to throw over the middle.

There it was, in full throat, the C-word. Criticism. Gee, this guy is still making mistakes, both reporters and chat rooms complained. Through it all, Flacco was impervious and resolute, mindful only of the next game, which in this case is Sunday's AFC wild-card rendezvous in New England against the Patriots.

"He's still Joe," quarterbacks coach Hue Jackson said Thursday. "He's been awesome. Joe will tell you I'm very critical of him and how he plays. That's my job. He never flinches, and that's why I love coming to work every day to work with a young man who wants to be one of the best players in this league."

Flacco threw for 2,971 yards and 14 touchdowns as a rookie, leading the Ravens to the AFC championship game. This year, he threw for 3,613 yards and 21 touchdowns. But he threw crippling interceptions against the Cincinnati Bengals and Indianapolis Colts, was battered by the Pittsburgh Steelers, was throttled by the Green Bay Packers, and won two fewer games in the regular season, proving that he had lessons still to learn.

And perhaps some of that criticism is the price Flacco pays for being the answer to the Elvis Grbac, Kyle Boller conundrum.

"The beautiful part about that is that here in Baltimore, maybe for the first time in a long time, there's an expectation at that position," Jackson said. "Criticism is good when you play quarterback because there is an opportunity to grow and get better. Without any struggle, there'd be no progress. So I think you have to have some struggles at times so that you do grow. … And I think he's very comfortable with what he is and what he's doing."

Consider this: Flacco has had the fifth-most productive first two seasons in NFL history, with 6,584 yards, behind Peyton Manning, Dan Marino, Drew Bledsoe and Jeff Garcia.

He is the fourth starting quarterback since the 1970 merger to reach the playoffs in his first two years, joining Ben Roethlisberger, Bernie Kosar and Marino. He has a two-year record of 22-13, including postseason, and runs the Ravens' no-huddle offense deftly with audibles.

How cool is Joe Cool? Ask him whether his comfort level has been bolstered by last season's playoff experience and he responds with a typical nonaffirmation.

"Last year I played 16 games, so I was pretty comfortable at the time," Flacco said. "I don't really treat playoff games any differently than I treat regular-season games. Every game in the regular season is just as important as this game's going to be."

Pressed for a better answer - or perhaps a more reflective answer - he said: "I don't know. I think I have [a better] comfort level because I've played more games and I've had more experience now, but I don't know if winning playoff games last year does anything or not. We'll see."

The Ravens were just 1-6 against 2009 playoff teams this season, and while Flacco completed 60 percent of his throws in those games, he also threw more interceptions (10) than touchdowns (eight). His best effort against the playoff field was a 385-yard, two-touchdown performance in Minnesota that should have been rewarded with a victory over the Vikings.

He threw four interceptions in a two-game sweep by the Cincinnati Bengals, and three in a late collapse in Green Bay against the Packers.

Flacco's second-season struggles get pushed behind his first-year success and the raw potential that former NFL stars like Shannon Sharpe and Phil Simms see in the 24-year-old from Voorhees, N.J.

"When you've got a quarterback like him, these guys don't come around often," said Sharpe, a playmaking tight end on the Ravens' Super Bowl team and now a commentator for "The NFL on CBS."

"When you've got a guy like this early on [in his career], sometimes you're going to have to take the good with the bad. He's made a few errant throws, but that guy can throw the out route from the far hash as good as anybody in the NFL."

Simms, former Super Bowl-winning quarterback for the New York Giants, will work Sunday's game in Foxborough, Mass. In a release issued by CBS, Simms said Flacco has not had a "sophomore slump," but made an insightful analogy to baseball.

"He's the hitter who might be hitting .250, but you never know when he's going to hit one out of the park," Simms said. "So that's what scares you and you have to be alert. He has a big arm and can make the big throws down the field that win games. And you always have to be conscious of that and protect against it. He's had a very, very good second year. Baltimore hit the jackpot when they drafted him."

In last week's playoff-saving road victory over the Oakland Raiders, Flacco completed just 11 of 19 throws for 102 yards, the lowest yardage total of his two-year career.

Offensive coordinator Cam Cameron was impressed by what Flacco didn't do - throw interceptions or turn the ball over in a field-position game. He wanted Flacco to take sacks rather than make risky throws, and when he could, throw the ball away if receivers were covered.

"I thought Joe took two great sacks and threw two great incompletions in the game, because that was the game plan," Cameron said. "There are some other games where you really have to take more risks than you want to. That game was a zero-risk game."

Cameron conceded that the Ravens will take a more conservative approach to the postseason - can anyone say 2000 Ravens? - but will not go overboard.

"In the playoffs, that is a critical element," Cameron said. "Now sometimes the score doesn't allow you to do that. An eight-point lead, or late in the game, it can change the game a little bit. Obviously, you don't want to turn the ball over. … At the same time, you're not going to win playoff games going into a shell as a play-caller or going into a shell as a quarterback. I can't guarantee you much going into this week, but those two things ain't going to happen."

Baltimore Sun reporter Kevin Van Valkenburg contributed to this article.