CHICAGO (AP) -- Larry Johnson was having so much fun he didn't want to leave the field. Considering how much time he missed, who could blame him?
Johnson showed glimpses of his old self, and Brodie Croyle hinted at what might be.
Back from a broken foot, Johnson ran for a touchdown on the opening drive and Croyle made the most of limited time to lead the Kansas City Chiefs to a 24-20 victory over the Chicago Bears in the preseason opener Thursday night.
"I didn't want to come out because I was having a lot of fun just running around," Johnson said.
Johnson had just 18 yards on eight carries, but there were enough familiar flashes to ease lingering concerns.
He burst through the middle, past Brian Urlacher, for a 7-yard gain on the second play from scrimmage and finished the drive with a 5-yard run. He had 18 yards on eight carries, meaning there certainly is room for improvement.
Meanwhile, Chicago's Kyle Orton fumbled, Rex Grossman stumbled and neither established himself as the leader in a quarterback race that could extend into the season. Bears coach Lovie Smith had said he won't rush his decision and neither gave him reason to reconsider.
"Both guys did some good things," Smith said. "Our team isn't ready to play the Colts yet. We'll go back to the practice field and next week we'll flip the order and go from there."
Orton started and completed 7 of 10 passes for 56 yards and no interceptions. But the Bears had to settle for a 42-yard field goal by Robbie Gould in the second quarter after Orton dropped the ball while scrambling, resulting in a 9-yard loss.
"I don't think you can hang your hat on one night to win any job," Orton said. "I played solid today, made the right reads and ran the offense. That's been my goal. As long as I continue to do that, I think I'll be fine."
Grossman came in late in the first half and wasn't much better, going 4-for-8 for 44 yards and a touchdown. He is expected to start at Seattle on Aug. 16.
Booed often at Soldier Field since the Bears drafted him in the first round in 2003, Grossman was greeted with near-silence when he trotted onto the field late in the first half. The jeers came on the opening drive of the second half when he threw an incompletion to finish a drive that went nowhere. He stumbled on the next possession, resulting in a 5-yard loss, but redeemed himself after Rod Wilson intercepted Thigpen, hitting Garrett Wolfe for a 25-yard touchdown that pulled Chicago within 14-10.
"When I did play ... it was all right," Grossman said.
A 13-yard touchdown pass from Caleb Hanie (9-for-16, 101 yards) to Brandon Rideau gave the Bears a 17-14 lead with 23 seconds left in the third. After Kansas City's Connor Barth kicked a 37-yard field goal, Gould put the Bears ahead 20-17 with a 37-yarder before Thigpen and Sippio connected on the winning pass.
It was a good night for a Chiefs team coming off a 4-12 season.
Croyle, a third-year pro with no wins as a starter, was 6-for-10 and didn't throw an interception. Damon Huard, who replaced him on the Chiefs' third series, made a case for the backup job while going 6-for-8 for 77 yards and a touchdown. Thigpen was 8-of-16 for 113 yards.
"Just seeing everybody in the locker room afterward -- everybody is happier, everybody is listening to music, everybody is talking, dancing, singing," Croyle said. "It's just night and day when you win and you lose."
The most encouraging sight for the Chiefs was having Johnson in uniform.
He missed most of training camp last year in a contract dispute after rushing for more than 1,700 yards in 2005 and 2006, and the second half of the season with the foot injury.
"Obviously, getting him back is going to get more people in the box, which is going to enable us to have one-on-one coverage outside, and I think we have the receivers to do it with," Croyle said.
The Chiefs were without rookie defensive tackle Glenn Dorsey, the fifth overall pick, after he sprained his left knee in practice over the weekend. Tank Tyler started in his place. They also held out LB Napoleon Harris, who was on the active list, because of a knee injury. ... Bears first-round draft pick Chris Williams underwent surgery to repair a herniated disc in his lower back. The 14th overall pick, Williams was expected to start at left tackle, but he has been sidelined since leaving the second practice with back stiffness. John St. Clair started at left tackle.