INDIANAPOLIS -- After rampant speculation in recent weeks whether Tony Kanaan would come out of his IndyCar retirement for a second time should race day storms in central Indiana on May 26 prevent Kyle Larson from making his Indianapolis 500 debut, Arrow McLaren personnel have decided to keep the 2013 500 winner on the timing stand Sunday, the team confirmed Thursday.

IMS and IndyCar were understood to have held a tentative one-hour block of track time Thursday afternoon for Kanaan to complete a two-stage, 30-lap veteran refresher that would make him eligible to fill-in for Larson, should a rain delay to the start of the 500 force Rick Hendrick to pull the NASCAR Cup points leader out and take him to Charlotte Motor Speedway to fulfill the series' rules on playoff eligibility.

But after team and IndyCar personnel continued dialogue around what would and wouldn't be permitted in the search for a possible reserve drive option for Larson early this week, Arrow McLaren has chosen to prioritize its race car prep for Sunday and the impact Kanaan can have in Larson's ear as Arrow McLaren's sporting director and the point man who has led Larson's development program since he assumed the role last fall.

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Last week, IndyStar learned that IndyCar had changed its rules around relief and reserve drivers that in the past had allowed drivers to hop in the cockpit mid-race for the car's starter. Most recently Robby Gordon bowed out of the 500 during a nearly two-hour rain delay in 2004 to be able to get to the Coke 600 on time, leaving Jaques Lazier to take over the No. 70 Chevy for Robby Gordon Motorsports when racing action returned. The No. 70 entry bowed out for good 88 laps in with a mechanical failure. Kurt Busch, the most recent driver to attempt 'The Double' in 2014 would've also been permitted to have a driver step in mid-race, or be tapped to start for him if he needed to leave before a delayed green flag, but IndyCar changed its rules shortly after.

Under the new regulations, teams are not permitted to have a second driver step in mid-race. They also are not allowed to ready a potential stand-in to start the race, if that substitution driver is not already cleared to compete, without withdrawing the previously planned driver from the field. As it applies to Larson and the No. 17 Chevy, under a strict reading of the rulebook, Kanaan would not have been allowed to take part in the refresher session needed to make him 'race-eligible' without first eliminating any chance of Larson starting. The only driver, then, allowed to start in Larson's place at the moment would be rookie Nolan Siegel, who was the lone driver bumped from the field over the weekend.

Rule 4.3.3.1 in IndyCar's most up-to-date rulebook states that, when it comes to oval races, the only drivers eligible to substitute for the original driver on the entry list would be ones that have participated in "practice or a special session" ahead of the race's start. But in recent days, IndyCar officials seemed willing to relax those rules, though it is not clear whether they had giving Arrow McLaren the green flag on getting Kanaan approved or not.

Leading into a weekend that features a tenuous forecast with showers likely to fall at some point, the decision by the team to prioritize its original plans opens the very real possibility that the No. 17 may not finish the 500. Larson's NASCAR team owner Rick Hendrick, who partnered with Zak Brown and Arrow McLaren on Larson's 500 debut, told reporters Tuesday it would be "very hard" and "very tough" to make any decision that would prevent Larson from taking the checkered flag, but he also didn't rule out the notion.

NASCAR's rules require teams and owners to start (or attempt to qualify for) all regular season, points-paying races that season in order to be eligible for the playoffs in the fall -- which Larson has already qualified for by virtue of his pair of wins that locks him into one of the 16 spots. Entering this weekend, he has a 30-point cushion as the championship leader. In the past, NASCAR has handed out playoff waivers for drivers who have missed regular season races due to injury but were otherwise playoff eligible due. It's presently unclear whether NASCAR would accept Larson and/or Hendrick outright choosing not to attend and compete in a Cup race in favor of the 500.

Though IndyCar would not require Siegel to partake in any special on-track session in order to start in Larson's place, it would also be surprising for the team to insert him into the biggest race of the year, should weather push them that direction, as his first time in Arrow McLaren equipment. In that vein, should weather create a situation where Larson would be unable to finish the 500 and make the Coke 600 -- and Hendrick opts to prioritize the Cup race -- either Larson (if he's at least able to stay for the race's start) or Siegel (if Larson already had to leave in order to make the Coke 600 green flag) may take the green flag, complete a single lap to signify having 'started' the race, and then pull into pitlane and shut the car off for the day.

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Doing so would mean the entry hadn't formally been withdrawn before the race, allowing it to be awarded the requisite prize money for last-place -- which can make a not insignificant difference for team members -- rather than none at all.

A team spokesperson told IndyStar Thursday that Arrow McLaren "will aim for any opportunity to have Kyle in the car," while acknowledging the possibility of a "game-time decision," if weather delays make both starting and running the full 500 and running the full Coke 600 an impossible combination.

With Siegel -- or anyone other than Larson -- in the car, the No. 17 Chevy would be forced to start 33rd on the grid, due to IndyCar rules around driver changes after qualifying -- similar to Graham Rahal starting 33rd a year ago when he took over the No. 24 Chevy for Dreyer and Reinbold Racing after Stefan Wilson's Monday post-qualifying practice crash that left him with a fractured vertebrae. Being forced to start in last-place -- and therefore being without a realistic chance to win -- is also understood to have played into the decision not to spend time readying Kanaan at the expense of fine-tuning the team's entries as they currently stand.

This article originally appeared on Indianapolis Star: Even if rain derails Kyle Larson's Indy 500 debut, Tony Kanaan will stay retired