INDIANAPOLIS, Ind. – Frank Gore never had the opportunity to play alongside the quarterback he envisioned when relocating to Indy during the 2015 offseason.

Not the real Andrew Luck.

Oh, he shared the backfield with the Indianapolis Colts’ cornerstone QB, but only for 22 games. Luck would miss 26 of 48 games, including all of 2017, and Gore was left wondering . . . What if?

He has perused video of the Colts, and wonders no longer.

“I’m happy for him, man. He’s ballin’,’’ said Gore, who returns to town Sunday when his Miami Dolphins visit Lucas Oil Stadium. “I know how much he loves the game of football and how he approaches the game.

“He’s back. I was checking him out early on and you could tell he was kind of timid. But now, man, he’s looking like that boy comin’ out of Stanford.’’

That would be Andrew Luck, circa 2012, and so much has transpired between then and now. General body trauma while playing behind a substandard offensive line, the lacerated kidney, a concussion, the January 2017 surgery to repair a torn labrum in his right shoulder.

Also, missing all of 2017 and the subsequent extended trips to the Netherlands and the West Coast for specialized and exhaustive rehab.

Last Sunday, Luck led the Colts to a fourth straight win – 38-10 over the Tennessee Titans – by authoring a fourth straight high-level performance. He passed for 297 yards and three touchdowns, missed on only six of 29 passes and finished with a 143.8 passer rating, the second-highest of his career.

“It’s pretty crazy,’’ Luck said after the game. “I was not in a good spot a year ago today. I remember that.

“I am in a good spot right now.’’

We could argue he’s never been in a better spot.

From that “timid’’ start – Gore’s observation – Luck has meticulously worked his way back. Day by day. Week by week. Month by month.

He has embraced the offense installed by Frank Reich and Nick Sirianni, and benefitted from an offensive line than has kept him relatively clean for the first time in his career. The Colts have allowed just 10 sacks on his 400 passes, none on his last 214 attempts. They’ve allowed no sacks in the last five games, a team record and tied for the third-longest streak in league history.

After Sunday’s blowout of the Titans, Reich was asked to offer context to where Luck was from a rehab/physical standpoint when he was named head coach in February to now.

“The context was, we were throwing little – I don’t even know what kind of balls they were – weighted balls. But they didn’t have points on them,’’ he said with laugh.

Nine months later, Luck is the AFC’s Offensive Player of the Week and on a historic run. Consider he has:

• Compiled passer ratings of 131.5, 125.6, 123.5 and 143.8 during the four-game winning streak. The only other Colts’ QB with four in a row above 120: John Unitas (1965). Peyton Manning had 82 games with a passer rating of at least 120 during his 208-game Colts career, but never was able to string four together at 120-or-higher.
• A combined rating of 135.2 over the past four games (74 percent completion percentage, 13 TDs, one interception). That’s second in team history to Unitas’ 135.4. The next two: Manning at 133.5 in 2004 and Manning at 131.2, again in ’04.
• The opportunity Sunday against the Dolphins to join Seattle’s Russell Wilson (2015) and the Chargers’ Philip Rivers (2014) as the only QBs in league history to post a rating of at least 120 in five straight games.
• Completed at least one TD pass in 33 consecutive games, a team record, the NFL’s longest-active streak and the eighth-longest streak in league history.
• At least three TDs in seven straight games, the third-longest streak in one season in league history. The only two that are longer belong to Tom Brady (10) and Manning (8).
• Maximized his options. Luck has spread his 29 touchdown passes among 12 different players. That’s one shy of matching the NFL record set by Atlanta’s Matt Ryan in 2016.

It’s been a collective effort involving the offensive line, the running backs, receivers and tight ends.

But it’s also been Andrew Luck returning to his old form, perhaps even exceeding what he once was.

“He’s been lights out, man,’’ center Ryan Kelly said. “He’s just been incredible. He’s been having a helluva lot of fun, too.’’

Reich never forgets to mention Luck’s supporting cast when assessing the play of his QB, but he also is quick to funnel credit where it’s due.

That would be in the direction of Luck.

“He’s special. He’s a special player,’’ Reich said.

The current four-game roll, he added, is “the byproduct of him being a special player and he’s getting good play around him.

“Make no mistake about it, he’s special.’’

Luck conceded he might be playing the best of his career.

“I’d like to think so. Maybe,’’ he said. “We’ve talked a lot about Frank’s perspective and how he approaches things and just getting better every day and not getting caught up in results as much as believing in the process.

“That’s part of what I’ve learned. Every day is about getting better. Shoot, even in a game it’s about getting better. It’s about being the best you can be and finding an edge.

“I’m not going to go and play the game of looking back and comparing and contrasting. It just doesn’t fly in my mind. But I do think that every week I feel a little better and a little better, and every day I feel a little better and a little better.’’

You can follow Mike Chappell on Twitter at @mchappell51.