INDIANAPOLIS (AP) — Colts center Ryan Kelly understands this week's challenge.

Make the right pass protection calls, and perhaps the Colts can add another chapter to their home mastery over Jacksonville. Make a mistake, and the Jaguars pass rushers could be off and running.

It's the kind of challenge the 2016 first-round pick embraces every week, though this one could prove especially difficult.

"It's a tough front seven," Kelly said. "Everybody knows the margin for error is pretty small in the NFL. If you miss one thing, they'll take advantage of that."

The stakes are pretty high for the Colts (2-4), who are one game out of the AFC South lead.

They're playing at home Sunday and hope to rebound from a rare loss to Tennessee on a short week.

On Wednesday, they found out star quarterback Andrew Luck was being temporarily shut down from throwing because of soreness in his surgically repaired throwing shoulder and their short-yardage specialist, running back Robert Turbin, might miss the rest of the season with an injured left elbow.

Indy's biggest concern this week is getting the seemingly ever-changing offensive line ready to face the league's top sack teams.

Indy has used a different starting lineup each of the past three weeks and three opening day starters — center Deyshawn Bond (quad), right tackle Denzelle Good (wrist) and right guard Jack Mewhort (knee) — are already on season-ending injured reserve.

Kelly, meanwhile, continues to knock off the rust after missing the entire preseason and the first four regular-season games with a broken foot.

The Jags (3-3) lead the NFL with 23 sacks and in turnover margin at plus-10, numbers that correlate with their successes and failures.

In three wins, Jacksonville has allowed 23 points, had 14 sacks and 11 takeaways. In three losses, it has allowed 87 points, had nine sacks and four takeaways.

So coach Doug Marrone is looking for his young team to start showing some consistency, starting in Indianapolis.

"One week it was special teams, the other week we didn't touch a guy when he was down. Another week there might have been turnovers," he said. "We're working our way through all this stuff and we've just got to learn to be more consistent on every down and in all three phases."

Here are some other things to watch:

FACING BRISSETT

The Jaguars will be facing quarterback Jacoby Brissett for the second time this season.

Jacksonville held two joint practices with Brissett's former team, the New England Patriots, in August and faced him in the preseason opener. Brissett completed 8 of 13 passes for 88 yards against Jacksonville, playing mostly against backups. He was traded to Indy on Sept. 2 and has started each of the past five games.

"(Brissett) is getting better and better each week and is really doing a nice job," Marrone said.

HILTON'S HELP

Last season's league champion in yards receiving, T.Y. Hilton, has 25 catches for 485 yards and one TD this season.

But more than half of those totals (14 receptions, 330 yards, one TD) came in victories over the winless Browns and 49ers. On Monday, Hilton was held to one catch for 19 yards.

This week, the Colts need more out of their Pro Bowl receiver against one of the league's best cornerback combos in Jalen Ramsey and A.J. Bouye.

"There a lot of factors that go into getting a guy involved," Indy offensive coordinator Rob Chudzinski said. "There were chances and opportunities to get him the ball (in Tennessee), and it just didn't come together. But he's always in the forefront of our thought process."

STACKED BOXES

Jags rookie Leonard Fournette is facing more eight- and nine-man boxes than anyone in the league.

He has a league-high 46 carries for 270 yards against stacked lines of scrimmage. The New York Jets and Los Angeles Rams may have established a blueprint for defending Jacksonville by using a number of fronts in hopes of slowing down the powerful running back. The Rams even played some goal-line defense in the middle of the field.

"We're going to have to figure out and adjust to it on the fly," quarterback Blake Bortles said. "I wouldn't be surprised at this point to see anything."

SECOND-HALF WOES

Indy hasn't trailed at halftime since its Week 1 loss to the Los Angeles Rams. But it has struggled to close out games for a variety of reasons.

The latest one, Monday night, was that when the Colts couldn't get first downs in the second half, the defense eventually wore down. If the Colts plan to stay in the division chase, they must find a solution.

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AP Sports Writer Mark Long in Jacksonville contributed to this report.

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