Zak Keefer | IndyStar

Matt Kryger/IndyStar

Matt Kryger/IndyStar

INDIANAPOLIS -- Observations from the Indianapolis Colts’ second minicamp practice on Wednesday:

More throws from Andrew Luck

As promised, quarterback Andrew Luck ramped up his throwing regimen on Wednesday, albeit very gradually.

A day after revealing he’s been throwing now for three weeks – and doing so publicly for the first time since Oct. 12 – Luck was back at it, running through individual drills with the other quarterbacks. He then took it a step further, participating with the other QBs in the routes vs. air portion of practice, tossing a handful of passes, including a 20-yard wheel route to rookie running back Jordan Wilkins. Those passes came with an official NFL football, as opposed to the high school ball Luck was tossing around Tuesday.

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The throws? Mostly short, simple and on target. Probably around 15-20 passes all told. Plenty of zip on them, too.

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Luck is scheduled to have Thursday off as the Colts wrap up the three-day minicamp. He’ll continue to gradually build his throwing regimen over the ensuing six weeks in an effort to more fully participate when training camp practices begin July 26.

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Can John Simon last at defensive end?

Matt Kryger/IndyStar

At this early juncture, it appears no sure thing. Simon – like Jabaal Sheard, like Tarell Basham – is moving from the stand-up, traditional 3-4 outside linebacker spot to the hand-in-dirt, 4-3 defensive end position. It’s a position Simon says he hasn’t played since college, and that was six years ago.

At 6-1 and 250 pounds, Simon doesn’t boast the prototypical size the scheme demands from the defensive end position. There are always exceptions – see: Mathis, Robert – and Simon is a terrific football player, undoubtedly one of the Colts’ best on that side of the ball. But the move remains questionable for a couple of reasons. For starters, it’s going to be a hefty transition. So far, Simon’s mostly been practicing with the second-team defense, behind Basham, a second-year player who didn’t exactly wow as a rookie.

Asked Wednesday about Simon’s progress at his new position, defensive coordinator Matt Eberflus stopped short of offering a glowing evaluation.

“Yeah, he’s been working hard,” Eberflus said, before diving into a tangent on a few former players who made a similar position switch. Asked then if Simon is undersized for the defensive end spot in this new scheme, Eberflus agreed.

“Yeah. What you have to do is use your attributes, your strengths, use your get-off, all those things. He’ll figure it out as we go.”

The major difference: the 3-4 outside linebacker spot is a thinking man’s position, where quarterback rushes are designed. Simon’s flourished there as a pro, both in Houston and with the Colts last season before a neck injury sent him to injured reserve. The end spot he’s being asked to learn is simpler, featuring a buffet of 1-on-1s against some of the biggest players on the football field: the offensive tackles. It’s about speed and it’s about power.

Does he feel like he’s too small for the job?

“As long as the coaches don’t think that, I’m in good shape,” Simon said Wednesday.

The second reason the move remains so puzzling: The Colts are exceptionally thin at all three linebacker spots. There are no entrenched starters, only a seemingly endless list of uncertainties. It’s hard to see Simon – one of the few pure defensive players on this roster – not being able to earn a starting spot there, perhaps at the SAM position.

Simply put: The Colts’ defense isn’t good enough to have a guy like John Simon play the wrong position – or worse yet, become a second-stringer. Training camp will reveal more, but for now, Simon’s unsettled status remains one of the more intriguing aspects to watch on this new-look defense.

Walker goes down

Matt Kryger/IndyStar

Second-year linebacker Anthony Walker, who’s seen plenty of snaps in the last few weeks with the first unit, went down during Wednesday’s practice. He remained on the field for several minutes before being carted off. The injury isn’t expected to be serious but no details were available. Coach Frank Reich did not address the media Wednesday but is set to Thursday.

Walker is among the candidates to start at one of those three linebacker spots, though it remains the most unresolved position group on the roster.

“I was just talking to the linebackers today,” Eberflus said. “I said, ‘Hey, we got 10 guys in here and we have no idea who’s 1 and no idea who’s 10. So the competition’s up in the air, and that’s at every position.”

While the Colts remain hopeful that second-round pick Darius Leonard will eventually earn the Will linebacker spot, he has remained sidelined all spring and summer with a hamstring injury. Walker, Najee Good, Jeremiah George, Antonio Morrison, Skai Moore and Tyrell Adams have all shuffled in and out of the starting spots, though nothing has been solidified. Eberflus noted that the evaluation will continue throughout the entire 2018 season.

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Best photos from Colts Mini Camp

Notes

One noticeable change in the tenor of practice this summer is the music. Chuck Pagano's teams would typically have the speakers blast during the stretching portion, then turn the volume down for the remainder of practice. (The one exception being during special team drills when the Colts were preparing for a road game they expected noise to be a factor.)

Under Reich, the music is blaring from start to finish. During a heavy rain Wednesday, the Colts actually turned up the volume, and a handful of players couldn't help but bust out some dance moves.

Call Star reporter Zak Keefer at (317) 444-6134 and follow him on Twitter: @zkeefer.

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Gary Varvel's cartoon history of the Colts