Part of the issue is that veteran quarterback Brett Favre, who did not arrive in Minnesota until Aug. 18, continues to try to gain familiarity with his wide receivers.
The fact top receiver Bernard Berrian did not play in the final three exhibition games and continues to be slowed a bit by a hamstring injury has not helped matters.
"I still think there's a lot of chemistry to be had," Favre said after the Vikings' 34-20 victory at Cleveland Browns Stadium. "It was evident on numerous plays."
The issue for Vikings' opponents is that if this offense begins firing on all cylinders it could be scary. Pro Bowl running back Adrian Peterson opened the season by rushing for 180 yards on 25 carries and three touchdowns, including a 64-yarder.
The addition of first-round pick Percy Harvin also has made the Vikings that much more dangerous. Harvin had three receptions for 36 yards and a touchdown in his NFL debut and returned three kicks for an average of 33 yards, including a 41-yarder that set up a touchdown drive.
All of this, of course, means that as Favre nears his 40th birthday on Oct. 10 he simply has to run the show and not star in it.
"He is coming along just fine," coach Brad Childress said of Favre. "Is he completely, completely comfortable? I'm not sure he's ready to make that assertion. He's smart enough to know that it takes time and reps, particularly when you move receivers around. He goes to school every week, but there is nothing like a game to show you what you've got."
Said Favre: "The best way to build chemistry is games. We're playing for real now and we're kind of learning on the fly because we did sputter a bit on the passing game. Brad and Darrell (offensive coordinator Darrell Bevell) were both trying not to overdo it but we needed to get a little spark going."
The Vikings are now hoping they Favre and his teammates will be able to keep that spark alive.
LINEUP WATCH: WR Darius Reynaud is clearly the Vikings' top punt returner. Reynaud returned two punts for an average of 27 yards in the Vikings' victory over Cleveland. That included a 36-yard return that set up a second-quarter touchdown. Reynaud is clearly comfortable catching punts, which is more difficult to fielding kickoffs because of the rotation of the ball.
BY THE NUMBERS: 5 and 9 - Number of sacks and quarterback hurries the Vikings had against the Browns. That means the Lions and QB Matthew Stafford should be feeling plenty of pressure Sunday at Ford Field. The scary thing for the Lions is that Pro Bowl DE Jared Allen did not have a sack or a hurry against the Browns.