Daniel Ricciardo has been described by his former Red Bull race engineer Simon Rennie as “hollow” upon his return to the Milton Keynes operation at the start of the year.

Currently sidelined with a broken hand, Ricciardo joined Red Bull as third driver this year prior to being seconded to Scuderia AlphaTauri to race for the Italian squad.

That was the culmination of months of work from both the Australian and Red Bull to rebuild him after a tumultuous four years away.

Ricciardo left the team at the end of 2018 to join Renault, where he remained until the end of the following season.

He switched to McLaren for 2021 where the then-seven-time race winner struggled to adapt to the nuances of his machinery, ultimately resulting in the decision to end the relationship a year early.

That saw a return to Red Bull in support of Max Verstappen and Sergio Perez, where he reconnected with Rennie in the team’s simulator.

The pair featured on the Talking Bull podcast where they reflected on the Australian’s return.

“The first thing I did in 2023 was a couple sim sessions,” Ricciardo explained.

“And that was, for sure, just for me to get back in the groove, to learn the car, but just kind of get back into my flow.”

At that point, Rennie interjected with his impressions of those early moments.

“I don’t think that was as easy as you thought it was going to be,” he ventured, a point acknowledged by Ricciardo.

“When he first came back I was quite surprised. Knowing Daniel, when he came back – I didn’t say this at the time – that he was almost like… you’re definitely not as confident as I know you are, and you were just a little bit hollow in a way.

“It felt like you were doubting yourself a little, and you were. You were a bit concerned about whether you could do it again, because obviously you’d had good success with us, and you’ve had the last couple years haven’t been quite successful.

“And it didn’t necessarily click straightaway in the simulator,” Rennie added.

“It took you that first day that we did together – I don’t know if you left with a good feeling or not after that first day, you still seemed a little bit unsure of it all.

“And then you want away, had a bit of time off at home, and then next time you’re in, it’s like you were a bit more bouncy.

“Maybe you had more time to think about it – you were a bit more like, say, halfway back to being yourself.

“Then we had a good day in the simulator and I think you just drove it naturally, like you wanted to do, and it just sort of clicked a little bit.

“The confidence from then snowballed and you built, and built, and built, and then by the end of that day, or the next day, you felt like, ‘yeah, he’s back again’.

“But it was really mad; the first time we saw him again, you were a bit subdued. It’s nice to see him back.”

Rennie’s comments echo those made by Red Bull boss Christian Horner, who has suggested Ricciardo was not the same person he was when he left the team at the end of 2018.

With the likeable Aussie having rediscovered his mojo, he made a good account of himself in the two races in which he drove prior to F1’s mid-season shutdown.

Sidelined through injury, Qatar now looks the most likely event for his return. New Zealander Liam Lawson is filling the second Scuderia AlphaTauri drive in the interim.