HOUSTON — During the first half of the season, the Houston Texans had problems beating the better quarterbacks.

The Texans are 4-4 entering Sunday’s game against Philadelphia at NRG Stadium. The Eagles’ Nick Foles qualifies as one of the best quarterbacks on the schedule.

If the Texans are going to finish .500 or better, they’ll have to defeat an above-average quarterback.

So far, they lost to Eli Manning (New York Giants), Tony Romo (Dallas), Andrew Luck (Indianapolis) and Ben Roethlisberger (Pittsburgh).

They beat Robert Griffin III (Washington), Derek Carr (Oakland), EJ Manuel (Buffalo) and Zach Mettenberger (Tennessee).

They have three games left against rookie quarterbacks — one against Mettenberger (Tennessee) and two against Blake Bortles (Jacksonville).

The Texans capitalized on the inexperience of Carr and Mettenberger. They took advantage of Manuel’s ineptness, and he was benched and replaced by Kyle Orton before the next game.

RG3 was coming off an injury and did not get comfortable in Jay Gruden’s new system during the opening loss to the Texans.

The five teams left on the schedule with winning records also have Foles, Brian Hoyer (Cleveland), Andy Dalton (Cincinnati), Joe Flacco (Baltimore) and Luck at quarterback.

The Philadelphia game should be a gauge of how the Texans are going to do against the best remaining teams.

One reason the best quarterbacks have defeated the Texans is because the secondary surrenders too many passes of 30 or more yards. In Sunday’s victory at Tennessee, they allowed completions of 48 and 43 yards.

The defensive backs force a lot of turnovers. The Texans have forced 17, second in the NFL to Buffalo. But there’s a price to be paid — too many big plays.

The better quarterbacks can adjust to J.J. Watt being the only effective pass rusher.

Bad or inexperienced quarterbacks can’t consistently take advantage of the Texans’ weaknesses. Good quarterbacks can.

If the Texans are going to improve and at least compete for a wild-card berth in the second half, they’ll have to pull an upset or two.

NOTES: WR Andre Johnson had 100-yard performances in two games against the Eagles. He had six catches for 101 yards in 2006 and was six for 149 in 2010. … ILB Brian Cushing is expected to miss a second consecutive game to rest a sore knee. With the bye week after the Philadelphia game, he should be healthy for the Nov. 16 game at Cleveland. … CB Johnathan Joseph is tied with Cushing for the team lead with 50 tackles. … QB Ryan Fitzpatrick is on a pace to throw 18 touchdown passes and 14 interceptions. … FS Kendrick Lewis had a hand in five of the Texans’ 17 turnovers — the most in franchise history through the first half of the season. He has forced three fumbles and recovered one fumble and has one interception.