Three weeks into the season, it’s clear Calvin Johnson and the Lions are once again relevant. (Genevieve Ross/AP)

Week 2 is when we can start seeing trends. No team wants to be 0-2. Everyone would love to be 2-0. The reality is that most teams will be 1-1 at the end of Week 2. So, two games in, most teams are on the same equal playing field they were on before the season even started. But, Week 2 will tell us if Week 1’s performances were aberrational or if they were trends. Got blown out in the first game? No big deal. Unless you also get blown out in game two. Poor blocking in Week 1? We can all forget about it if it’s remedied by Week 2. But if you got blown out in Weeks 1 and 2, or your poor blocking was exposed both weeks, now we have a trend.

Week 3 is when we can really start seeing what each team has and doesn’t have. By Week 3, you largely are who you are going to be. If you don’t have a passing game for three weeks, it seems unlikely you’re going to find or develop one during the season itself.

Well, we’re three weeks in. And here’s what those three weeks have to tell us:

1) The Lions are for real. Barring injury (and please just assume everything going forward is prefaced by those same words), they should scare most teams on both sides of the ball. Ndamukong Suh appears to be even more dominant than last year, and Stafford-to-Johnson should remind everyone of Warner-to-Fitzgerald.

2) The Bills are real-ish. Coming from behind from 20 points two weeks in a row tells us a lot about their character. Falling behind by 20 points in the first place? That tells us something else, now doesn’t it?

3) The Vikings are in for a long season. In fact, take the last paragraph about the Bills and turn it upside down. Good teams win games when they go into the locker room with large halftime leads.

4) The Eagles and Falcons are both 1-2. That doesn’t mean that either is a losing team. (And, in fact, except for the possibility of a tie, one of them had to lose their Week 2 game against each other.) What it does mean is that the Eagles aren’t going to steamroll their opponent each week (just like the other “Dream Team,” the Miami Heat, didn’t), and the Falcons won’t catch anyone by surprise this year. Not when Peter King of Sports Illustrated picks them to reach the Super Bowl. No one is giving either team a free pass to the postseason.

5) The Titans’ Chris Johnson has picked up fewer yards in three games than he usually gets in a quarter. He’s going to break out at some point — right??? — but it tells us two things. One, training camp means something. And, two, teams are keying on him, which is only going to get worse if Kenny Britt is out for the season.

Mark Sanchez and his broken nose could use some better pass protection. (Robert Galbraith/Reuters)

7) The Jets got up for the Cowboys game (which Tony Romo almost literally handed to them), didn’t need to get up for the Jaguars game (gracias, Luke McCown and your 1.8 QB rating for the game), and by some accounts appear to have taken the Raiders too lightly. They seem to be a greatly overrated team. Losing Shaun Ellis and Jason Taylor on defense appears to have had some effect. It certainly doesn’t appear that they have as much confidence in Shonn Greene as they’ve claimed. And Nick Mangold’s high ankle sprain? They’re a different team without him, as the Raiders and their fans will attest.

8) Kevin Kolb’s the real deal in Arizona. Yes, they may have overpaid for him, but right now, who cares?

9) Donovan McNabb got old fast.

10) Calvin Johnson, Larry Fitzgerald and Andre Johnson are spectacular. Bet you wish your team had one of them.

11) Last season, the Packers hit their stride just as the playoffs began as they came to grips with some significant injuries. This season, they hit their stride from the opening kickoff. Or at least their offense did. But that defense will come around. They won’t go undefeated, but only an injury to Aaron Rodgers (again, the “I” word) is going to stop them from a spirited title defense.

12) The Texans should be a playoff team . . . only because the Peyton Manning-less Colts are not.

13) Sorry, Seahawks fans. Sorry, Rams fans.

14) And really sorry, Dolphins fans. If you can’t win at home, and you can’t win at Cleveland, it’s going to be a long, long season.