The 210cm ruckman joined the club through the 2021 Mid-Season Draft, crossing from rugby union just two years prior in linking up with Sydney's Academy program.
A fresh calf setback for veteran tall Tom Hickey will see the journeyman miss the start of the season, while a knee complaint for Peter Ladhams ruled him out of Friday's pre-season clash against Brisbane.
The pair of injuries saw McAndrew carry a majority of the ruck workload against Lions pair Oscar McInernery and Darcy Fort at Tramway Oval, with the fledgling Swan impressing his coaches
“He battled well," Sydney assistant Dean Cox said.
"I think when you're playing against two number one rucks, or people that have played a lot of senior footy, to be able to learn.
"It's a massive learning curve for him, he's come a long way in a short period of time.
"He got to test himself against a quality opposition which was really pleasing."
McAndrew managed 12 matches for Sydney's VFL side in 2022, a campaign highlighted by a two-goal, 27-hit-out performance against Coburg in Round 9.
Rookie Will Edwards was also thrown into the ruck mix, with the key defender's stint in the middle coming amid injury concerns for both Hickey and Ladhams.
A tendinitis issue for Ladhams isn't expected to keep the former Port Adelaide player out of next week's pre-season match against Carlton, with the Swans likely to rely on a two-punch ruck setup with McAndrew sharing the hit-out duties.
That match frames as an opportunity for McAndrew to stake his claim for a debut in Round 1, with Cox noting the pre-season presents an exciting window.
"He'll get a bit of an opportunity against some experienced Carlton ruckmen," Cox said.
We have added to our ruck stocks with our pick number 12.
Welcome QBE Sydney Swans Academy and VFL player Lachlan McAndrew to our list! pic.twitter.com/Q3HlEMwp6T
— Sydney Swans (@sydneyswans) June 2, 2021
"That's a good part about this time of year. You can try things, throw people in and see how they go."
Sydney and Carlton will clash in Blacktown next Friday afternoon, with the Swans then turning their attention to their season opener against the Gold Coast Suns at Carrara on March 18.