With Arrow McLaren expanding to three full-time entries for 2023, Rossi arrives at the team with seven years of experience at Andretti Autosport.
And while O’Ward is not expecting favours from his new team-mate, he firmly believes that Rossi will be a big help in developing Arrow McLaren’s set-ups.
"At the end of the day, as much as team-mates will help in order to gather data, it doesn't mean they're going to specifically help you in what you need, because it's a series where you can really tailor the car to what you want, rather than like, for example, in Formula 1 – ‘This is the car, you need to learn how to drive this certain car', he said.
"In IndyCar it's very different where you can really tailor and customise it to what you want it to feel like or drive like.
"From past experience, I think Alex likes a car similar to what I do. I know he likes it to be able to point well.
"From experience – I wasn't at Andretti seven years like Alex was – but from my experience, it was an extremely strong car in the rear.
"I feel like our car is very different to that. I'm curious to see what he thinks and how he kind of develops where we can find some more time.
"I do think we have a very strong car in certain areas, but I definitely think he's coming from a team where that car has been stronger than us in other racetracks.
"I feel like if we can just find gains where we haven't quite had a winning car, a podium car, that's just going to help all of us, right?
"He's been great to have around. I think he needed a fresh start. I think he's excited to really work with all of us, create the strongest package."
As in 2021, O’Ward scored two wins last year but his fortunes took a gut-punch thanks to two mechanical DNFs, at Road America and Mid-Ohio, in which he could have finished top five in the former and won the latter.
The end result was that he took only seventh in the championship after finishing fourth and third in the previous two seasons.
"For sure it's been looked into," said the 2018 Indy Lights champion on McLaren's mechanical dramas.
"We've obviously looked for answers. Have we found them all?… It's a hard statement to say because I feel like you can find and analyse reasons of why things might have happened, but you never really know for sure.
"But what I do know is that we want to minimise those. The perfect thing would be to not have those issues, right?
"It's possible, for sure. I mean, the first two years I was with the team, I never had a DNF! I completed almost all the laps all year.
"Last year, we had the best average qualifying positions that we had during a season. But we had, like, four DNFs. One of those was maybe unlucky, the other ones were just a mishap.
"For sure it's possible to make those a lot less than they were last year. Last year was for sure not a fluke, but I was very surprised because we had never had those issues, at least to that extent."
O’Ward insisted that his Formula 1 ambitions, following his tests with the McLaren F1 team, would not be a distraction for him in the season ahead.
"All the F1 stuff is more of an off-season project,” he explained. "My focus and all my attention will be in IndyCar for the next good amount of months.
"But obviously it's been more than enjoyable. It's been fantastic. A big part of my off-season before going home, it was really focusing on the F1 stuff.
"I'm also excited to go back to IndyCar now because it always feels a little odd when you go from one car to the other. Takes a few laps to get back into the sync of things, really feel it out…
"We will put our full focus into our IndyCar season; then I'm sure the F1 stuff will come shortly after."
