Kansas City Chiefs coach Romeo Crennel wants to make sure that the disaster that was in early 2011 does not repeat itself in early 2012.

Crennel has put much more emphasis on the preseason than his predecessor Todd Haley. Haley took it easy on the team during the preseason and watched them go winless and then start the regular season with two blowout losses. Three months later, he was jobless. 

So when the Chiefs got off to a sloppy start and an early 14-0 hole in Saturday's 31-17 loss to St. Louis, Crennel was not pleased. 

"Not enough focus, not enough concentration on a week when we were breaking camp and all of those kinds of things," Crennel said, via the Kansas City Star. "That just showed we're not mature enough yet. We have to play a lot better if we're going to have a chance to win in the NFL."

The performance was the exact opposite of the first week against Arizona when Kansas City jumped out to a 14-0 lead and the starters looked sharp. 

"They got us on our heels a little bit right at the start," LB Derrick Johnson said. "Good play-calling on their part. A little adversity hit, which is good for us after we played so [well] last week. It's not time to panic, of course. We've got to go back to work this week. Coach Crennel stressed that right off."

Lewis injures shoulder: Safety Kendrick Lewis had his arm in a sling after the loss to the Rams, the Kansas City Star reported. Lewis injured his right shoulder while making a tackle in the second quarter. Lewis never returned to the game. It was the same shoulder Lewis had surgery on after last season.

Bowe visits with team: Dwayne Bowe visited with teammates Friday night before they made the trip to St. Louis. Bowe signed his tender and will begin practicing this week after missing training camp.

"He came in and met with everybody and was happy to be back," WR Dexter McCluster told Josh Looney of KCChiefs.com. "We're happy he's back too. He looked good to me, even showed us his abs to prove he'd stayed in shape."

Bowe will try to quickly learn new offensive coordinator Brian Daboll's offense before the regular season opener on Sept. 9 against Atlanta. 

"He's a whole training camp behind," Crennel said. "There's a lot. New offense, new terminology -- there's lots of stuff that he has to learn."

Stanzi takes blame for his performance: Ricky Stanzi took the blame for his poor performance on Saturday, which likely put him behind in the competition with Brady Quinn for the backup QB job. Stanzi was sacked four times and threw an interception in four scoreless series. 

"That was my fault," Stanzi said of the interception. "I threw it into some tight coverage. It makes it tough for the receiver. I could have gone somewhere else with the ball on that one. ... I've to get rid of the ball. You can't put that kind of pressure on the offensive line to hold up for that amount of time. I've got to be able to get the ball out of my hands and move the chains."

Follow Chiefs reporter C.J. Moore on Twitter @CBSSportsNFLKC and @cjmoore4.