Before the Eagles begin play every year, there are some things about how the season will go that we suspect, some that we don’t know, and some about which we are absolutely sure.

Most of the time, the suspicions, hunches, and firm beliefs turn out to be utterly unreliable. Which games will be won and lost is the most unreliable guesswork of them all. Show me the fan who ticked off the schedule back in April and put both an “L” next to “home versus Detroit,” and a “W” next to “at Green Bay four days later,” and I’ll show you someone who did the exercise blindfolded.

The Eagles have gone through one-quarter of the regular-season schedule now, and move further into the unknown this Sunday against the Jets. One thing we do know is that the Eagles have played the Jets 10 times in franchise history and their record is 10-0. Among active franchises, the Houston Texans are the only other team against which the Eagles have a spotless record (5-0).

In what has been an interesting, although imperfect, start to the season, maybe the Eagles can at least hang on to that bit of perfection in the record book.

To catch up, let’s review the top five “Things We Thought We Knew” about the Eagles 2019 season and how those have gone so far.

1. The Eagles changed doctors again, so all that injury stuff is over now.

Yes, for the second straight offseason, the Eagles shook up their medical staff, and, to be honest, 2018 was no bargain in terms of player injuries. Not to suggest that anyone wasn’t doing his or her job properly. That’s what the guys in legal like to call “libel,” and we’ve got enough problems. But whatever it was, the team changed direction again, which is something none of the cornerbacks could do by the end of last season.

Well, 2019 hasn’t exactly gotten off to a good start on that front, either. If flies have hamstrings, then the cornerbacks are falling like flies once more. There is a shortage of experienced defensive tackles as well, and, at one recent count, 11 of the 22 projected starters on offense and defense were suffering with some malady or other.

Given the need to use backups and to adjust schemes on both sides of the ball, the biggest surprise so far might be that the Eagles are holding their own at 2-2.

2. You don’t fix a bad running game with a rookie and a downside veteran.

The jury is still out on this one, and deliberations might take a while, so send in some lunch. Actually, the only reason deliberations are continuing is that the Eagles running game finally showed signs of life against the Packers last Thursday night.

In the first three games of the season, the Eagles totaled 299 yards on the ground, averaging 3.6 yards per rush, 25th in the league. Against Green Bay, Miles Sanders and Jordan Howard combined for 159 yards, and Howard bulled in for two touchdowns. (He also had a receiving touchdown.)

Prior to that game, Sanders had looked like a jittery rookie, and Howard had looked like a fourth-year player whose drafting team traded him away because his production had gone down each season. What changed? There are theories, some of which indicate that the Packers stink against the run, that the Eagles offensive line clicked into place after not playing together much since last season, or that Sanders and Howard magically improved in four days.

We’ll see. One game is not a real trend, but it was better than the previous trend.

3. If Carson Wentz is healthy, he is above criticism.

Hoo boy, on this one. The quarterback is apparently healthy, although he’s been banged around a bit, and, as far as we know, has no lingering issues from the back fracture he suffered last season.

He’s cruising along with a respectable 95.3 quarterback rating, and has thrown nine touchdowns and just two interceptions this season. Aside from the loss in Atlanta, where he had a bad night, Wentz has a rating of over 100 in the other three games, and zero interceptions in those games.

After the Detroit loss, however, a game in which Wentz threw for 259 yards and would have probably had another 100 if anyone could catch the football, Wentz was criticized locally for not lifting the team all by himself.

It brought to mind the old Charles Barkley routine after it was said, in comparison to Magic Johnson, that he didn’t make the players around him better: “Oh, I’d like to have to make James Worthy better. That must be really tough. I have to make Shelton Jones better.”

4. DeSean Jackson is the answer to everything that ails the offense.

Well, sure, if he’s playing. He was playing in the opener against the Redskins and caught two touchdown passes of 50 yards or more, and racked up 154 receiving yards on eight catches. He took the top off the Washington defense, although, admittedly, it doesn’t appear to be screwed on that tightly.

Those catches are also the last ones he has made this season. Jackson left the Atlanta game after just 11 snaps with an “abdominal” injury and hasn’t been seen since. (Just a heads-up. That usually means a “sports hernia,” although no one has come out and said it yet, and, obviously, if I were a doctor the Eagles would have hired me at some point. They go through them fast. So, maybe it’s a tear in the muscle wall – a hernia -- but maybe not.)

In any case, this gets back somewhat to No. 1, but Jackson will turn 33 this season, and the last time he played every game was his final season in Philadelphia. Counting this season, he has fully missed a total of 16 games since then, spending the equivalent of an entire season on the sideline.

5. Nothing really matters because the Cowboys suck and the division is ours.

Oops. Dallas did have a bit of a downturn last weekend against New Orleans, but the Cowboys are no joke. There’s no question they beat up on three mediocre teams in going out to a 3-0 start, but it wasn’t just the caliber of the opposition.

Both sides of the ball are talented, and quarterback Dak Prescott appears to be benefiting from the revamped offense of new coordinator Kellen Moore. The most mind-boggling stat regarding the Cowboys is that they have converted 52.4 percent of their third-down attempts, while opponents have converted only 26.5 percent.

That disparity will settle down at some point, but those aren’t numbers that happen by accident one-fourth of the way through the season.

At least, that’s What I Think I Know right now. Check back in another four weeks and we’ll all know a lot more, and a lot less.