INDIANAPOLIS –Final Thoughts, Detroit Lions at Colts Preseason Game 1: Rookie Kenny Golladay catching on quick, and what to see from other draft picks. First look, offensive line – left tackle in the spotlight. Check List: Play time projections, and three undrafted rookies who can help their case as longshots.

1. Step up for Golladay: It's hard to recall a third-round draft pick who has stirred as much intrigue from Day One. Golladay hasn't stumbled on any step in his rookie progression. As he heads into his first preseason game, Golladay looks like he fits as the No. 3 receiver with veteran starters Golden Tate and Marvin Jones Jr.

Golladay's size (6-4, 213) is an asset, but so has been his learning curve. He spoke at the end of the week about learning the little things – like winning on routes when he's not the primary receiver.

"It's funny that you said that," Golladay told a group of reporters. "Our coach (Robert Prince) said that to us just now. He said we had some pretty good routes out there. Even though we didn't get the ball, that's going to show up on film.

"He said, 'Even though you didn't get the ball, keep winning. You're one of 11.'"

The point is, Matthew Stafford finds the open man – whoever he is, and wherever he is in the progression. It's important for receivers to run routes like they're going to get the ball – because they will if someone else is covered.

What does he want to accomplish against the Colts?

"I want to take all those good things to Sunday," Golladay said. "Let it all come together and unfold, and hopefully I do great.

"Just take it day by day – stack good days on top of good days."

2. QB protection unit: Fair or not, the offensive line is in focus more than ever this year, and the most intense scrutiny is on the left tackle. What would have been a strength is a question mark because of the shoulder injury sustained by Taylor Decker, whose play as a rookie in 2016 marked him as an anchor up front for a decade.

The battle is on between veterans Greg Robinson and Cyrus Kouandjio for the starting job until Decker returns. Robinson has taken the most reps with the No. 1 unit, but the pecking order can change from week to week in the preseason, depending on performance – or lack of it.

The sooner that position is settled satisfactorily, the better.

Elsewhere up front, the unit will settle into place by the start of the season. Right guard T.J. Lang has had limited practice time to make sure he is fully healed from offseason hip surgery when the regular season starts.

3. Eye on the draft picks by round:

1. LB Jarrad Davis: It's performance and leadership – how he makes plays and makes calls as the new leader in the middle. Everything suggests he can handle the entire package, but this is the start of showing that in game conditions – with more to come.

2. CB Teez Tabor: There is less need for him to make an immediate impact than some lower picks because of depth at the position, but his development is important.  Tabor seems to have a good feel for the game, and the temperament to handle the hazards of playing cornerback. It will be interesting to see what he does with a chance to make a play on a ball.

4. LB Jalen Reeves-Maybin: Pursue and make plays, particularly on special teams, to add depth at linebacker.

4. TE Michael Roberts: A big man with big hands can make an impression as a short-range target and scoring threat in the red zone. He should get more snaps against the Colts with Eric Ebron likely to make his preseason debut next week.

5. CB Jamal Agnew: Actually, he's No. 3 on my list of draft picks to watch behind Davis and Golladay because of the possibility he could be major producer in special teams. He had a long punt return for a touchdown in last week's mock game at Ford Field, but that was without all-out contact.'

Even in the preseason, there can be lights-out contact. Agnew will get some work as a backup cornerback, but the return game is his best chance to make an impression.

6. QB Brad Kaaya: The battle for the No. 2 QB job ramps up. Jake Rudock has a sizeable advantage. If he's going to close the gap, Kaaya has to be accurate throwing the ball and efficient running the offense.

6-7: DT Jeremiah Ledbetter, DE Pat O'Connor: Do what Anthony Zettel did as a sixth-round pick last year. Make plays, and play smart.

Check list:

Playtime: Stafford and most of the offensive starters played one series in Game 1 last year, but it was a 13-play possession, plus a penalty, and it ended on a sack and a fumble. Stafford also ran once on that play, and had a good gain on a scramble called back on a penalty.

Look for the same for Stafford in this game, assuming he has no lingering soreness from bumping knees with Ameer Abdullah in Friday's practice against the Colts.

Expect a similar snap count for the other starters – including Abdullah, who went out for the season in Game 2 last season with a foot injury. Some game action – such as contact, reacting to blocking angles – cannot be simulated in practice.

Undrafted rookies to watch: Defensive end Alex Barrett, tight end Robert Tonyan, running back Tion Green.

The odds are stacked against them, as it always is against undrafted free agents. But all three have had something in common: Good things seem to happen when they're around the ball.

The three rookies need look no further than teammates at their own position for evidence of how undrafted players can make it in the NFL. Tight ends Darren Fells and Cole Wick, running back Zach Zenner and defensive end Kerry Hyder Jr. all landed jobs without being drafted.

Someone's always next.