The most encouraging development early in this Dolphins season. And playing time news.

A 10-pack of Miami Dolphins notes/thoughts on a Friday, in the wake of their 31-13 win at Jacksonville:

▪ Besides winning, the priority for Year 2 of this Dolphins rebuild must be identifying what positions need to be addressed and which seemingly are fixed, at least fixed to the point that early-round draft capital need not be invested.

Crafting any “fixed” list in September is premature, but this much is heartening: If rookie left tackle Austin Jackson and rookie right guard Solomon Kindley continue on this arc, the Dolphins will not be compelled to invest any of their five early-round 2021 draft picks (two firsts, two seconds and third) on the offensive line.

Impending free agent center Ted Karras, left guard Ereck Flowers and right tackle Jesse Davis (backed up by rookie second-rounder Robert Hunt) have been solid.

As for the rookie starters, “Solomon is a mauler,” Karras said Friday. “It’s fun to play next to a guy like that who can move bodies and clean out the pocket. Austin, 21 years old playing left tackle in the league, is very impressive. I told those guys I was very impressed with them, proud of them. They’re doing a lot of great things.”

The fact neither rookie starter has allowed a sack through three games is something that shouldn’t be glossed over, not after watching left tackle Julien Davenport permit 18 sacks over his first 26 starts for the Texans and Dolphins.

Entering this weekend, 23 NFL guards (including pricey ones such as Brandon Scherff and Zack Martin) and 24 NFL offensive tackles have allowed sacks. Jackson and Kindley have played more games (three) than nearly all of the others and still haven’t relinquished one.

Three of the offensive tackles selected before Jackson was picked 18th overall in April — Andrew Thomas, Jedrick Wills and Mekhi Becton — already have relinquished a sack. Thomas, who was selected fourth by the Giants, has allowed nine pressures.

This isn’t to suggest either Dolphins rookie has been perfect by any means; Jackson has allowed six quarterback pressures and Pro Football Focus ranks Kindley as the sixth-worst run blocking guard in football so far, one spot ahead of Flowers. (These rankings are obviously subjective and Kindley has looked better than that to me.)

But Kindley had an excellent block on Ryan Fitzpatrick’s second-half TD run and as a rookie fourth-round starter has exceeded all expectations. And it’s impressive that these two rookies have been highly competent without any preseason games and an on-field offseason program.

“Kindley gets a couple years in the weight room, he’s going to be destroying people,” Fox’s Troy Aikman said. “He’s a mauler.”

▪ Thursday’s strong effort by Shaq Lawson was vitally important because the Dolphins really need to make it work with him, with Lawson still due $7.9 million in guaranteed money after this season. He had six pressures and graded out best among all Dolphins defenders on Thursday, per PFF.

The next five on the list of top Dolphins defensive graders against Jacksonville: Xavien Howard, Andrew Van Ginkel, Kamu Grugier-Hill and Kyle Van Noy.

▪ The Dolphins’ worst defenders on Thursday, per PFF, were Davon Godchaux and Elandon Roberts, and notably, both saw their playing time plunge.

Godchaux played only 28 of 66 defensive snaps, while Zach Sieler logged 31 snaps and played well, per PFF. Brian Flores explained that he stuck with the “hot hand” in Sieler.

The biggest front seven change made since the opener was dramatically increasing Sieler’s role and reducing Raekwon Davis’; the Alabama rookie - who struggled in the opener and played better in Week 2 - logged just 13 defensive snaps in Week 3.

▪ As for Roberts, he allowed all three passes thrown against him to be caught for 37 yards on Thursday, was faked out badly on the Jaguars’ first play (a 24-yard gain on a screen to James Robinson), and played only occasionally after the first drive (20 defensive snaps in total). The Dolphins, in retrospect, might have been better off keeping Raekwon McMillan, despite his shortcomings against the pass.

It’s notable that the Dolphins aren’t always playing Van Noy as an every down player; he played 52 of 66 defensive snaps on Thursday, with Jerome Baker playing 59. Lawson played 42, while Grugier-Hill and Andrew Van Ginkel logged 20 apiece. Sam Eguavoen played his first defensive snaps of the season (two).

▪ The slot cornerback position remains a conundrum, with nobody yet emerging. On Thursday, Jamal Perry played 41 snaps and Tae Hayes 15.

Against the Jaguars, Perry allowed all four passes in his coverage area to be caught for 33 yards, including three first downs.

Hayes permitted an 18-yard completion Thursday and committed a questionable pass interference penalty but deserves another chance, after allowing only three completions in 16 targets in his December Dolphins cameo.

Nik Needham, who struggled last week, didn’t play a snap on defense.

Once Byron Jones recovers from his hamstring injury, it would behoove the Dolphins to try Noah Igbinoghene in the slot, though the rookie said he has been working exclusively on the boundary in practice.

▪ I’ll always wonder what would have changed if the Dolphins hadn’t regrettably made Kalen Ballage the lead back to start last year - and then promoted Mark Walton to that role - which led to Kenyan Drake requesting a trade and rejecting Miami’s offer of a contract extension.

Since moving to Arizona, Drake has 789 yards rushing on 5.0 per carry in 10 games.

Would you prefer Drake at his $8.4 million 2021 salary or Jordan Howard ($5 million) and Matt Breida ($3.3 million)? I’d prefer Drake.

Myles Gaskin has been a wonderful story (152 yards rushing, 4.0 per carry and 15 catches for 91 yards), but one of Miami’s five picks in the first three rounds of next April’s draft might need to be allocated to running back, perhaps Clemson’s Travis Etienne or Oklahoma State’s Chubba Hubbard.

But give Gaskin his due. Playing sparingly last year “was a humbling experience, makes you hungry not playing the game you love,” he told me.

Howard, incredibly, now has 12 yards on 16 rushes — a year after Ballage set the record for lowest average by an NFL back (1.8).

On Thursday, Gaskin played 46 offensive snaps, Breida 11, Howard 4 and Patrick Laird 1. Breida had just three carries for four yards on Thursday, Howard three for one yard.

▪ Offensive coordinator Chan Gailey continues to make ample use of a fullback; Chandler Cox played 16 snaps on Thursday and now has 41 offensive snaps this season, compared to 66 all of last season. PFF ranks his blocking 10th of 14 fullbacks who are getting playing time.

▪ We like rookie safety Brandon Jones’ physicality and speed, but his coverage skills concern me. On Thursday, he allowed all six passes in his coverage area to be caught for 53 yards.

For the season, the numbers against him are 11 for 11 for 88 yards.

That’s why I wouldn’t be eager to insert him in the slot cornerback battle.

Bobby McCain continues to play the most of the Dolphins safeties (he was on the field for 64 of Miami’s 66 defensive snaps on Thursday), while Eric Rowe’s snaps have diminished somewhat (48 on Thursday) to make room for Brandon Jones, who played 39.

Rowe’s pass coverage metrics were second-best among all safeties last season after he moved there in October, but he hasn’t been as good early this season (5 of 6 caught against him for 34 yards on Thursday).

▪ Quick stuff part 1: Per PFF, the Dolphins’ highest-graded players on offense on Thursday were, in order, Jakeem Grant (only eight offensive snaps), Ryan Fitzpatrick, DeVante Parker, Isaiah Ford and Adam Shaheen….

Miami’s 18-point win was its largest margin of victory since a 26-point win against Denver on Dec. 3, 2017….

The Dolphins’ 12-play, 84-yard touchdown drive to open the game was their longest since Sept. 12, 2011 against New England, when they had a 12-play, 84-yard touchdown drive on Monday Night Football.

▪ Quick stuff part 2: Miami had 12 first downs in the first quarter, the first time the Dolphins had more than 10 first downs in the first quarter of a game since at least 1992….

The Dolphins scored touchdowns on each of their first three possessions for just the second time since at least 2000. The other instance: Nov. 20, 2011 against Buffalo….

The Dolphins had 17 first downs in the first half, tied (with a 2015 game against Tennessee) for the team’s most first downs in a first half since at least 2000....

For the fifth time in head-to-head competition in the past two weeks, a regular season NFL game outdrew the NBA playoffs. But Thursday night was by far the closest: 5.4 million people watched Dolphins-Jaguars on NFL Network; 4.6 million people watched Game 4 of the Lakers-Nuggets Western Finals on TNT.

Here’s my Friday piece on how well Xavien Howard and Noah Igbinoghene played on Thursday and everything Brian Flores said during his Friday press conference.

Here’s my Friday piece on what Ryan Fitzpatrick accomplished Thursday after historians rummaged through NFL record books.