The second round of the NFL playoffs start Saturday. This is when things really start to get interesting. The further we get into the playoffs, the more attention the general public pays to the games, and the more money they bet on the games. That means that the lines are going to be under more pressure now than they are in a regular season game. The line movements in playoff games can be particularly useful in getting a sense of what's going on and what the smart money is thinking about the games. Here's a look at how the four lines are moving:

Arizona Cardinals (+7) at New Orleans Saints (Saturday, January 15, 4:30 pm ET) - The line opened at a touchdown, and it doesn't seem to be moving anywhere. One book has moved it to eight points, but the rest have yet to budge, and it's quite possible that they won't. Two-thirds of the bets placed have been on the Cardinals as the public are clearly impressed by what Kurt Warner did last week and concerned about the struggles of the Saints at the end of the season. Given the proportion of the bets, though, it seems reasonably likely that the smart money is leaning towards the Saints. The interesting thing in this game is the total. The game opened at 57.5. Given the power of these two offenses and the ridiculous display the Cardinals put on last week the first instinct would be to expect it to climb regardless of what the number is. It hasn't. It is down to 57 in most places, and can even be found at 56. That actually shows some surprising restraint from the public - this total is higher than either team has faced all year, so it's impressive and a little surprising that the public didn't heavily bite on the ‘over’.

Baltimore Ravens (+6.5) at Indianapolis Colts (Saturday, January 15, 8:15 pm ET) - The books did a sound job of setting lines this week. The line on this game opened at 6.5, and has mostly stayed at that level, though it can be found at six as well. The action is balanced between the two teams, so the line isn't likely to make a big move, and is unlikely to hit the key number of seven. The total has been locked in place at 44. Given how public Peyton Manning and the Colts are in the playoffs, it's interesting to see the respect that the Ravens are getting. I guess that it didn't hurt their perception that they knocked off the most public team in the league in impressive fashion last week.

Dallas Cowboys (+2.5) at Minnesota Vikings (Sunday, January 16, 1:00 pm ET) - This line was opened at either three or 2.5 depending upon the book, and it hasn't move significantly since then. The action is close to split between the two teams, with slightly more - about 56 percent of bets placed - on the Cowboys. The number was well picked here - people who believe in the Cowboys will be thrilled that they are the underdogs, but the Vikings' backers will be happy that they don't have to give up the key number of three. Given that Dallas has looked so strong recently and the Vikings have faltered this number seems to have been well picked to keep the action reasonably balanced - just like the others we have looked at so far this week.

New York Jets (+7) at San Diego Chargers (Sunday, January 16, 4:40 pm ET) - Finally, we have a line that is actually making an interesting move. The Jets were 9.5 point underdogs when this game opened, but they have now dropped so the Chargers are only favored by the key number of seven. This has happened despite the number of bets being split fairly evenly between the two teams, so it is a pretty good indication that the smart money was all over the Jets early on. That's quite remarkable when you consider that the Chargers have won 11 games in a row and are looking as good as any team in the league. It's clear that people are buying into the power of the Jets defense and the efficiency of their running game. Either that or they believe in the bravado of Rex Ryan.