Who’s ready for Round 3?

Pretty much everyone will know I’m not talking about boxing, but Saturday’s AFC Division playoff game pitting the Steelers and the Baltimore Ravens.

Why aren’t we surprised it’s come down to this?

All season, the two AFC North squads stayed close and split their two games against one another — the Ravens won 17-14 at Heinz Field Oct. 3 and the Steelers won 13-10 Dec. 5 in Baltimore.

The Ravens could have captured both games. They used a late Joe Flacco touchdown pass in their win. In the second game, Troy Polamalu stripped Flacco of the ball to set up Pittsburgh’s game-winning drive.

The Steelers know they let one get away Oct. 3, but they got a reprieve when Polamalu saved the day yet again.

Remember in the AFC championship game two years ago? Polamalu had the game-sealing interception for a touchdown.

Polamalu always has played some of his best games against Baltimore, particularly in the playoffs.

He holds the key to this game as his presence makes a big difference. You could say he played when the Steelers lost to Baltimore, but the Ravens had just 10 points before the late scoring strike — and quarterback Ben Roethlisberger was serving his suspension.

Roethlisberger is another interesting point. Since opening his career 2-2 against Baltimore, Roethlisberger has guided the Steelers to six consecutive victories against the Ravens.

He has the Ravens’ number for now, but is he due to drop one? How lucky can he be against a team as perennially strong as the Ravens?

One thing is certain: this will be the primary NFL game out of the four this weekend. No one is talking about the NFC — Chicago vs. Seattle and Green Bay vs. Atlanta, in case you wondered — it’s been Pittsburgh-Baltimore and, to a lesser extent, the New England Patriots and the New York Jets.

The Jets knocked off the Pats earlier this year, then New England crushed the Jets 45-3 on “Monday Night Football” a few weeks ago. Had that game been closer, there might have been more interest.

No, Pittsburgh and Baltimore will be the biggest game of the year, and don’t be surprised if it’s one of the most watched games in the past few years.

You know what to expect: a hard-hitting game, players limping off left and right and a viable Super Bowl-caliber team advancing. The average score of this game the past four years has been 18-17 Steelers.

I’m not picking a winner or a score. I want to sit back and enjoy the best rivalry in the NFL.

And for the second time in three years, we’ll need three games to see why.