IndyCar's hybrid engine rollout will be delayed for the third time -- from 2022, the original target when plans were announced in the summer of 2019 -- now targeting the second half of the 2024 schedule, it announced Thursday afternoon. The release, confirming that the new technology wouldn't make its planned debut for the March 10 season-opener in St. Petersburg, came hours after an IndyStar report Thursday morning noted multiple sources' concerns regarding an ever-shrinking production timeline to outfit all 10 teams and 27 full-time cars with the new power unit in the next 90 days.

Though IndyCar's release notes the planned rollout will take place "after the 108th Indianapolis 500," as well as "during the second half of the (2024 season)," a series spokesperson confirmed there's no official target date.

Last week, IndyCar scrapped plans for testing this week that would've given six teams their first shot to run the unit, the first concrete move hinting that the series and its engine manufacturers would struggle to have the device in each teams' hands -- with the proper number of backup devices -- by March 10.

Multiple sources have told IndyStar that teams yet to run the full new unit expect to make their hybrid testing debut in January, but no formal target date has been set. IndyCar on-track hybrid testing of any kind has also been shelved until the new year.

At the moment, just four teams have turned laps with the prototype device that combines the 2.2-liter, twin-turbocharged V-6 engine with an energy recovery system that will build an energy bank from drivers braking, or manually choosing to harvest it (depending on the final regulations). According to IndyCar, 13 drivers (the full three-driver lineups at Andretti Global, Arrow McLaren and Team Penske, as well as four of five at Chip Ganassi Racing) have tested at seven different tracks and amassed 15,256 miles with the whole unit since it debuted Aug. 16 at Sebring.

Initial report: IndyCar delays 10-team hybrid test, rollout for start of 2024 in question

Complications around the COVID-19 pandemic constituted the first round of delays in IndyCar's hybrid rollout with the system's debut shifting from the start of the 2022 season to 2023. Continued supply chain issues were revealed in March 2022 that bumped that back to 2024, and a year and a day ago, IndyCar and its OEMs announced they would forego pairing the still-in-development hybrid unit with a brand-new 2.4-liter V-6 engine in favor of the 2.2-liter version that had been in use since 2012.

Due to shortcomings with supplier Mahle, which had been tasked with developing the hybrid unit, Honda Performance Development and Chevrolet/Ilmor were forced to take on increased roles -- investing more time, money and resources -- to get the device to the finish line, making the simultaneous development of a new internal combustion engine too much.

Multiple sources intimately involved in the testing program have reiterated to IndyStar that each test this fall continued to breed "momentum" and "positivity," despite the expected occasional issues, and one even said they were "surprised" to learn last week that testing had been called off for December.

Even still, concerns centered around the pace at which the process was going, how quickly HPD and Chevy/Ilmor would be able to crank out new units and the ever-approaching March deadline of St. Pete, have existed for some time, sources say.

"The partnership between Chevrolet and Honda has been phenomenal," IndyCar president Jay Frye said in a release. "The IndyCar-specific hybrid power unit is dynamic, and an engineering marvel, and we're completely committed to its successful introduction next season."

This article originally appeared on Indianapolis Star: IndyCar confirms delay of hybrid rollout, now targeting mid-2024 debut