Walker has kicked seven goals over the past two matches, leading Adelaide to back-to-back wins against Gold Coast and St Kilda.
Speaking to Triple M’s Roo & Ditts, Walker said his work on the training ground was starting to pay off.
“My first couple of weeks I wasn’t jumping at the ball, and I know that,” Walker said.
“As a big bloke, it’s (high marking) the last thing that comes back.
“Off the back of last year, I wasn’t anywhere near the level I wanted to play at.
“I’m starting to mark a few more, which is nice.”
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Despite the rumours, Walker denied claims he has been working one-on-one with AFL legend Wayne Carey to improve his marking.
“I love Wayne Carey, but it’s incorrect,” Walker said.
The Crows started the season slow with one win from four, but Walker doesn’t believe clubs need more pre-season matches to be ready for the premiership season.
“You have trial games, so you’re playing anywhere between two and five games (in pre-season),” he said.
“I didn’t do enough aerial training early on.
“But now I’ve got enough for some confidence heading into the games.”
Walker also threw praise on big defender Alex Keath, picking him as an All Australian based on the first six rounds.
“He’ll hate this, because he hates praise,” Walker said.
“He’s a very humble guy (and) he’s in my All Australian team.”