Sunday’s NFL schedule features four games between undefeated teams, but in Week 2, not all undefeated teams are created equal. Certainly, very few fans are expecting defending champion Indianapolis to lose to Tennessee, even on the road. The other three games are a bit harder to call.

TEXANS (1–0) at PANTHERS (1–0)

Sunday, 1 p.m.

Houston and Carolina each present a good example of why fans must avoid jumping to conclusions after the first week of the season. Since every team is 0–0, fans don’t consider opponent strength as much as they would later in the season.

Both the Texans and the Panthers looked good in their first wins, primarily because they were playing against bad teams. Houston beat Kansas City, which is a total mess on offense and may end up the year as the worst team in the league. Carolina and St. Louis were tied 7–7 when Rams left tackle Orlando Pace suffered a season-ending shoulder injury in the second quarter; the Rams’ offense fell apart without him and the Panthers won 27–13.

The Panthers had higher expectations entering the season and are significantly favored in this game, but an upset is not out of the question. Since the Texans have a poor secondary with the exception of cornerback Dunta Robinson, the best strategy to beat their defense is to spread the ball around. But Carolina’s offense is still overly dependent on a single player, wide receiver Steve Smith. Still, even if the Panthers have trouble scoring on the Texans, that doesn’t mean Houston will score enough to win. For the sixth straight season, Houston’s offensive line is a work in progress, which should mean a field day for Carolina defensive ends Julius Peppers and Mike Rucker.

VIKINGS (1–0) at LIONS (1–0)

Sunday, 4:05 p.m.

Both the Vikings and Lions want to prove that they are not alsorans in the NFC North, and both looked good on opening day — by defeating even worse opponents, Atlanta and Oakland respectively. Still, the winner of this game does get to enjoy a 2–0 start and a little bit of hope.

The Vikings had the best run defense in the league last year but were just mediocre against the pass. The Lions ran the ball less than any other offense last year, and they do nothing but pass. Minnesota has a pair of underrated cornerbacks, Antoine Winfield and Cedric Griffin, but it will still be tough to cover Roy Williams, Mike Furrey, and rookie Calvin Johnson, all at the same time.

When the Vikings are on offense, they don’t have a single good receiver who can take advantage of Detroit’s inexperienced secondary. It will be up to rookie running back Adrian Peterson to slash through the mediocre Lions’ front seven.

It seems like a terrible matchup for the Vikings, and yet they swept the season series a year ago, when the two teams had roughly the same personnel except for Johnson and Peterson.

CHARGERS (1–0) at PATRIOTS (1–0)

Sunday, 8:15 p.m.

This is the best game of the weekend, but the excellent strategic battle between two of the league’s best teams will unfortunately be overshadowed by controversy.

Most coverage of this game will concentrate on the recent disclosure that the Patriots have been breaking NFL rules by taping the opposing teams’ signals on the sidelines. There is sure to be plenty of discussion comparing the current four-game drug suspension of Patriots safety Rodney Harrison to last year’s fourgame drug suspension of Chargers linebacker Shawne Merriman. There will also be talk of last year’s shocking New England victory over San Diego in the playoffs, and San Diego’s accusations that Patriots head coach Bill Belichick told his players to dance at midfield when the game was over.

The Chargers outplayed the Patriots in that game, and lost on a couple of unlucky bounces, particularly the interception fumbled away by safety Marlon McCree. This year, it is more likely that the Patriots will win on their own merits. The new Patriots wide receiving corps of Randy Moss, Wes Welker, and Donte’ Stallworth has a huge advantage over San Diego’s weak secondary. Tom Brady won’t have as much time to throw as he did against the Jets, but the offensive line did a good job holding off the Jets blitz last week and a good job holding off Merriman in last year’s game.

New Patriots linebacker Adalius Thomas should help improve the defense against All-Pro tight end Antonio Gates, although as Chicago learned a week ago, it is impossible to shut down Gates completely. If the Chargers win, they’ll do it with reigning MVP LaDainian Tomlinson, who has gained at least 160 yards and scored two touchdowns in each of his last three games against New England.

Mr. Schatz is the editor in chief of FootballOutsiders.com.