Team Penske shifted the Brazilian veteran from IndyCar to the IMSA SportsCar Championship at the end of 2017, and he went on to score five wins in the Acura Team Penske ARX-05 over the next three seasons, culminating in winning the 2020 Prototype crown with Ricky Taylor.
He made sporadic IndyCar appearances during this period with Penske and Arrow McLaren SP before embarking on a six-race programme with Meyer Shank Racing in 2021 that yielded a fourth Indy victory.
Castroneves, who also won the Daytona 24 Hours in 2021 for Wayne Taylor Racing, added a second-consecutive victory in the IMSA blue riband for MSR this year ahead of a full-time IndyCar programme.
But results have proven harder to come by on his full-season return to open-wheelers, the highlight so far this year being seventh at the Indy 500, with team-mate Simon Pagenaud scoring the team's best result in second at the first Indy road course race.
However, the 47-year-old has rejected the subject of possible retirement, stating prior to this weekend's IndyCar round on the Gateway oval: “Obviously you get to a point that you’ve got to realise. As of right now, I don't feel that in my gut: I feel I have a lot left in the tank.
“The age is just a number. It's about understanding, especially with this new car, even for a veteran, experienced guy like myself, the car changed.
“When you don't have practice and things like that, it's become very challenging.”
Castroneves said he and MSR were “finalising some small details” about their contract for 2023, but admitted that he had been surprised at the problems he had faced re-acclimating to IndyCars following the adoption of aeroscreens for 2020.
“I didn't expect how difficult it was,” he said.
“We are making some changes internally to make sure these last three races, we continue to improve.
“This aeroscreen literally threw a curveball. To find a sweet spot is taking longer than I expected for myself to adapt and to understand what the car needs.
“We’re always one side or another. We're never able to find it.
“You see good drivers, guys that used to be in the series longer, have those inconsistencies, as well. But we’re pushing.
“I feel like we could be better. But remember, it's the first full-time season that I'm in. Certainly we're preparing for bigger things in the future.”
MSR has a technical alliance with Andretti Autosport, but Castroneves says that pooling the data from six cars doesn’t necessarily speed up the adaptation because of the differing driving styles which can become “a little bit confusing”.
“Sometimes it's difficult to teach an old dog a new trick, right?” he said. “You just got to really keep pushing and trying and find that sweet spot.
“But I have confidence enough, particularly as Andretti has not been this year that strong. They're showing great potential towards the end of the season, which is great.
“Some things we share, but sometimes we're just not able to get what they have. They've been very transparent, which is great, but we also need to do our own part.
“Everything is different for our team – first time a two-car car operation for Meyer Shank Racing. Simon is doing a great job.
“My guys [on] #06, incredible, all new guys compared to last year. A lot of people might not know that – all new group. We're all synchronised, as well.
“It's frustrating sometimes, but we have belief and trust in each other that we can make the result that we deserve.”
