HOUSTON -- Five games into the Brock Osweiler era and Houston Texans coach Bill O'Brien has been cornered into defending a quarterback who, despite the hefty free-agent price tag, has performed no better than the collection of mediocre signal callers the Texans employed after running Matt Schaub out of town on the nearest rusty rail.

With Osweiler underperforming again in a road loss to the Minnesota Vikings last Sunday, an effort that included his seventh interception this season, the chorus of discontent only swelled. The Texans (3-2) invested $37 million guaranteed in Osweiler over two seasons hoping that he'd offer an improvement over the Ryan Fitzpatrick-Brian Hoyer-Ryan Mallett hodgepodge working under center in recent seasons.

Instead, the Texans have received more of the same at a greater cost. With the Indianapolis Colts (2-3) coming to town on Sunday and first place in the AFC South up for grabs, the Texans' offense ranks among the worst in the NFL. Osweiler is part of the issue.

Only two quarterbacks have thrown more interceptions than Osweiler: Fitzpatrick (10) with the Jets and Buccaneers second-year quarterback Jameis Winston (eight). With Osweiler taking every snap this season, the Texans' passer rating (70.6) ranks 30th in the league, as does their yards per pass play (6.0). Their 208.6 passing yards per game is 29th in the NFL.

"I think Brock is working very hard," said O'Brien, who relieved offensive coordinator George Godsey of play-calling duties two weeks ago. "He's very prepared. I think all of us, including himself, we all have to do a better job. I'm sure he'd be the first one to tell you. Look, he's got to improve in this area, that area, you know all those things.

"I think overall I've been happy with the way the guy prepares. Not happy with the way the offense has played. Not blaming it on anybody. Really taking responsibility for it here, right here because that's where the responsibility lies when you're the head football coach."

With Osweiler as the focal point offensively, the Texans ranks 27th in yards per game (310.4), 30th in scoring offense averaging 16.4 points and 31st in yards per play (4.7).

And while Osweiler has struggled with ball security, the Texans' issues offensively extend to the running game where another free agent, Lamar Miller, has yet to score despite 101 rushing attempts. His 371 rushing yards are fifth in the AFC and ninth in the league, but Miller is averaging just 3.7 yards per carry, well below expectations given his speed and past reputation as a constant threat to score.

The Texans have struggled with injuries on their offensive line -- three-time Pro Bowl tackle Duane Brown made his debut against the Vikings -- but averaging 3.8 yards per carry represents woes greater that health and getting Miller acclimated.

"I can promise you the way we study the tape as an offense, the way our coaches prepare us, the way our coaches coach us up throughout the week, especially after games when we break down that film, I can promise you we're getting better every single week," Osweiler said.

The Colts have dealt with their own issues on the offensive line, both in terms of health and productivity. They invested four draft picks in the line this past spring and three of those draftees -- center Ryan Kelly, guard/tackle Joe Haeg and tackle Austin Blythe -- have started for the Colts this season.

With right guard Denzell Goode returning from a back injury last week against the Bears, the Colts trotted out their optimal offensive line, relegating right tackle Joe Reitz to the bench. Yet they surrendered five sacks en route to a shootout victory.

Colts quarterback Andrew Luck has been sacked a league-high 20 teams for a league-leading 126 yards. He still ranks among the top five in the league in completions (second, 131), attempts (third, 205), yards (fourth, 1,469) and touchdown passes (tied for fifth, 10).

The Colts are fifth in the NFL in scoring at 27.4 points per game, but keeping Luck upright has been a problem and is a priority.

"I think maybe a bit too much is being made out of that," Luck said of the number of hits he has taken. "I think just go out, play football. Getting hit can be part of the position and part of it."

Colts coach Chuck Pagano said, "You don't want your quarterback hit. Period. We're trying to do everything possible to make sure that doesn't happen and limit that. He knows that and everybody knows that."