Those expecting Jay Cutler to immediately transform the Chicago Bears into a pass-happy offense had better be patient.

Cutler came out throwing against Buffalo in his Bears' preseason debut Saturday night, but missed as many attempts as he completed _ not including the one he had intercepted in a 27-20 loss. So much for the much-anticipated buzz _ including all the No. 6 Bears jerseys sold _ that centered on the Pro Bowl quarterback Chicago acquired in a blockbuster offseason trade with Denver.

The Bills' offense, even minus Terrell Owens, out nursing a sprained toe, was much more efficient in 80-plus-degree and muggy conditions. And Buffalo got plenty of help from its defense, which generated four turnovers, including two interceptions by rookie Ellis Lankster.

Bills starter Trent Edwards finished 10 of 10 for 79 yards, and backup Ryan Fitzpatrick went 13 of 16 for 143 yards. The Bills broke open the game early in the fourth quarter by scoring twice in 34 seconds, both scores set up following Lankster's interceptions of third-string quarterback Brett Basanez.

Bills third-stringer Gibran Hamdan hit rookie Shawn Nelson for a 3-yard touchdown to put Buffalo ahead 20-13. Then Bruce Hall scored on a 4-yard plunge. Combined, Buffalo's four quarterbacks went 29 of 34 for 265 yards.

Buffalo defeated Chicago for only the second time in 14 preseason meetings (2-11-1), and bounced back from a 21-18 loss to Tennessee in the Hall of Fame game last weekend.

It was an uninspiring performance from a Bears offense counting on Cutler to provide a spark. He went 5 of 10 for 64 yards and an interception on a poorly under-thrown pass up the left sideline that was picked off by Leodis McKelvin. Cutler nearly threw another interception, but cornerback Reggie Corner dropped the ball that hit him squarely in the chest.

Cutler keyed mostly on Devin Hester, who caught only two of six passes thrown his way for 22 yards. Cutler's best throw came when he hit Desmond Clark in stride up the right hash mark for a 30-yard completion that set up Robbie Gould's opening 23-yard field goal.

Cutler couldn't take advantage against Buffalo's second-string defense and facing a short field after the drive began at the Bills' 43 after Dominic Rhodes muffed a punt.

Give it time, said Cutler, who noted the Bears rested starting running back Matt Forte and starting tight end Greg Olsen.

"We're just calling base stuff and seeing what happens out there right now," Cutler said at the half. "As soon as we start getting into the game plan, really nailing stuff down, that's when it's really going to count."

Bears coach Lovie Smith wasn't entirely impressed.

"It's a start," Smith said. "There are some things we would like to have back, but you have to have a starting spot. ... We'll build from here."

Bears backup Caleb Hanie had a better outing, finishing 8 of 11 for 87 yards, including a 14-yard touchdown pass to Will Ta'ufo'ou. Basanez bounced back, hitting Juaquin Iglesias for a 10-yard touchdown. Gould hit two field goals, including a 50-yarder.

Bills safety Donte Whitner was impressed with how the defense limited Cutler to three points and only two first downs.

"We're excited to come out here and start fast and clean up all the mistakes we've made," Whitner said after the defense gave up two touchdowns on the first two series against Tennessee.

Rhodes scored on a 3-yard run, while Rian Lindell hit two field goals.