But as an older brother, Jesse knows it's down to his mentoring that teenager Casey has become a fixture at the NRL premiership heavyweights.
Jesse McLean had appeared in the mix for more first-grade action when fellow outside back Stephen Crichton left the Panthers after their third consecutive premiership in 2023.
Instead, a serious concussion and back-to-back collarbone fractures stymied the older McLean in 2024, with Taylan May and Paul Alamoti preferred in the backline.
By 2025, Casey had jumped Jesse in the pecking order.
Still only 19, Casey hasn't looked back, playing 23 of a possible 27 first-grade games last year and helping the Panthers claw their way off the bottom of the ladder into a preliminary final.
He most recently ran for 144 metres and threw the last pass for one of four tries in Saturday's 26-6 defeat of fellow heavyweights Cronulla.
There are times older brother Jesse finds it hard to be routinely beaten for selection by Casey.
"As a competitor, I do. It's like anyone, if someone gets picked over me (it's hard)," the older McLean told AAP at the launch of the NRL's Multicultural Round.
"But I see it as an older brother. (I'm) just happy for him, proud of him."
And if not for Jesse, 19-year-old Casey knows he may not have made such a fast start to life as an NRL player.
"It all started at training - if he's not there, I'm not as comfortable," Casey said.
"Being able to have that familiar face around the whole time, it was a soothing factor, I suppose. I've got someone to hang out with, like at school."
It's brother Jesse and father Willie, who played six games for North Sydney in the 1990s, giving Casey honest feedback after tough games.
"(Jesse) is the one that tells me the truth," Casey said.
"He's kind of the last line of defence. I go to him, my old man. They're real special to me."
As it stands, three-time premiership winner Izack Tago appears next cab off the rank should an injury hit the Panthers backline.
But with both brothers contracted at Penrith through 2028, Casey is hopeful there's still time to share the field regularly with Jesse.
The pair had that chance last season in the notorious round-12 loss to eventual wooden spooners Newcastle, and when Casey was briefly dropped to NSW Cup.
"It felt like I was playing backyard footy again," Casey said.
"Being able to run out alongside my brother on a consistent basis would be really cool."
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