CINCINNATI — Andrew Luck watched one of his backups struggle behind an offensive line that remains the Colts' biggest concern heading into the season.
Coach Chuck Pagano has little more than a week to piece something together.
Rookie Jeremy Hill ran for 70 yards and was Cincinnati's top receiver as well on Thursday night, leading the Bengals to a 35-7 victory over Indianapolis in a game devoid of starters.
Luck and Bengals quarterback Andy Dalton sat it out, as did most of the starters for both teams.
The Colts (0-4) wanted to see how their backups performed because they'll be needed to help them get through injuries on the offensive line.
It wasn't pretty.
"We've got a lot of injuries," Pagano said. "We don't have a lot of time."
The Colts are so thin on the line that they used defensive end Tyler Hoover at left tackle to see how he'd fare.
"He came here as a defensive lineman," Pagano said. "He played a little bit of it and actually got some scholarship offers for it coming out of high school. He played offensive tackle and defensive tackle. We had depth at the defensive line and wanted to move him over there two or three weeks ago."
"They'll see if I have the potential to help out or not," Hoover said. "All I did was think positive thoughts and play my heart out."
Cincinnati (2-2) pulled off three big plays in the second half against the backups of the Colts (0-4).
Dane Sanzenbacher returned a punt 77 yards for a touchdown. Safety Danieal Manning intercepted Harnish's pass and ran it back 33 yards for a score. Cobi Hamilton turned a short catch into a 50-yard TD.
Harnish, who is third on the depth chart, went 13 of 24 for 102 yards with five sacks. Now he has to wait and see what the Colts decide to do at the position.
"It is stressful for sure, especially after a lackluster performance," Harnish said. "I'll just let the chips fall where they may."
Harnish threw a 7-yard touchdown pass to Da'Rick Rogers, who kicked the ball in celebration and was penalized. Pagano pulled Rogers aside on the sideline.
"It's unacceptable," Pagano said of the unsportsmanlike conduct penalty. "It does not represent anything we're about. I apologize to our fans."
Hill, a second-round pick who backs up Giovani Bernard, carried 20 times and had a team-high six catches for 70 yards. He hurt his right elbow late in the first half but returned.
Colts linebacker Robert Mathis didn't play, heading quietly into his four-game suspension. Mathis was suspended for breaking the league's policy on performance-enhancing substances and can't be with the team for the next month. He said he took a fertility drug to help his wife get pregnant.
Bengals linebacker Vontaze Burfict sat out a day after he signed a three-year contract extension that will pay him a maximum $20.05 million through 2017. Burfict strained his right hamstring on Sunday during a preseason game in Arizona.
The game drew 42,020 fans — leaving more than 23,000 empty seats — and was sloppy with so many backups on the field.
On one play, Harnish overthrew receiver Donte Moncrief so badly that the ball flew behind the helmet of Rogers, who was getting ready to block on the play. The Colts had a fourth-and-2 at the Cincinnati 10-yard line and went for it, only to have Zurlon Tipton tackled in the backfield.
Notes: Colts G Joe Reitz hurt his left ankle in the first quarter. X-rays were negative. The injury was diagnosed as a high ankle sprain. ... LB Andrew Jackson had cramps in his lower right leg and had to be helped off in the closing minutes. ... Bengals LB Sean Porter suffered a hamstring injury in the first quarter, Cincinnati's only setback.