Maroons legend Lockyer likened Walker to the great Allan Langer, who had his detractors before becoming one of the greatest Origin players of all time.
With the long-term injury to incumbent Maroons half Tom Dearden, the door is open for Walker to force his way into the side with a dominant display against North Queensland at Magic Round on Saturday.
Maroons selectors will meet Sunday night to pick the side for the May 27 Origin series opener in Sydney.
Lockyer rubbished suggestions Walker's defence would prevent him from being considered.
"I remember when I played, people questioned my defence too," Lockyer said.
"I think it just motivates you to want to be better at it. I suspect the talk around Sam and his defence this week – and with a lot of eyes watching him this weekend - that will be a real focus for him."
Wayne Bennett has said that Walker reminds him of Langer for his unpredictability and capacity to do things other players dream about.
"When you compare Sam to Alf, there are a lot of similarities. Obviously he is at the start of his career," Lockyer said.
"People questioned whether Alf could do it because of his size and defence but Alf could do things other players couldn't with his short-kicking game and ability to read the game."
Walker, 23, now has 95 NRL games under his belt and has proven himself on the biggest stage.
"I'm feeling really confident in my footy at the moment. It's out of my control but I know if the call came, I'd be ready," Walker said at the launch of the Beer Footy Food Festival this week.
"It's something I always dreamt of as a kid. All I can focus on is playing my best footy for the Sydney Roosters. The rest will take care of itself."
Walker was called into Maroons camp in 2023 and soaked up the euphoria of a Queensland win at Suncorp Stadium in the decider. The experience was memorable under the guidance of head coach Billy Slater.
"I only had that one camp with him. I was a pretty young kid and I was pretty excited," Walker said.
"He was really calm and collected. I was in there for game three when they got the win. It was a pretty cool experience."
The Maroons have positions up for grabs in the backs and forwards and Lockyer said "a lot hinges on what happens this weekend" in terms of who Slater will select.
"For a lot of players on the fringes, Magic Round is very significant," Lockyer said when asked if Broncos playmaker Ezra Mam was in contention.
"Obviously Queensland is a bit decimated with injuries so when that happens you have to look at all different combinations and scenarios.
"Billy is very good at analysing things and breaking it down and understanding what he needs to have in terms of back up."
