ST KILDA forward Patrick McCartin's mind must be ticking after he kicked seven goals with Sandringham in the VFL last week, but once again missed selection for Friday night's game against Greater Western Sydney.

The Saints' decision is understandable from a hard-nosed football perspective.

It's tough to find a spot for him in a forward line that includes Nick Riewoldt, Josh Bruce and Tim Membrey, particularly while Riewoldt is not running from a wing while his knee stabilises.

However, McCartin's non-selection also adds to the impatience of many observers who wonder when he is going to get a chance, particularly after the strange messaging that surrounded him being withdrawn late from St Kilda's round one team due to "hamstring awareness".

Despite missing that game against Melbourne, McCartin played the following day for Sandringham and kicked three goals.

The 21-year-old then played rounds two and three at AFL level before returning to the VFL as soon as Riewoldt came back from a knee injury. He's stayed there since, with the now-familiar answers from club officials about developing young key forwards being used when his name is raised.

Supporters know the drill: be patient, he's working on a couple of areas and we know he will be an outstanding player for the Saints in the future.

However, with McCartin's improved fitness this season, his great hands and his status as a No.1 pick, such non-selection is again bound to cause speculation. He would get a game with almost any other team in the competition.

It's why Geelong should be keeping a keen eye on McCartin as he shapes as a perfect successor for Tom Hawkins.

Raised in Geelong, McCartin is a loyal person who no-one doubts has his heart set on building a career at the Saints.

However, one imagines playing at Simonds Stadium in front of friends and family on a regular basis would have some attraction.

McCartin would have the benefit of Hawkins' experience as the veteran Cat enters the twilight of his career while he begins to assert his marking power in a comfortable environment.

Having similar players in the same forward line might be a challenge for the Cats, particularly with Daniel Menzel inside 50, but they have the emerging Nakia Cockatoo and Lincoln McCarthy as pressure forwards.

It's interesting to compare the career trajectory of Hawkins and McCartin as youngsters.

After 19 career games, Hawkins had kicked five bags of three goals or more on his way to a tally of 25.

He was big and capable of taking lesser opposition apart, but was clearly still learning to rely on more than bulk to play his role.

At the end of his third season, Hawkins was a premiership player, but didn't come of age until the finals series of his fifth season when he turned the 2011 Grand Final Geelong's way in the second half.

Now, at 29, Hawkins remains a vital cog in Geelong's forward line after 10 years as a key Cat.

But he will need replacing soon, and McCartin would be an ideal target even if the Cats have to wait until he comes out of contract at the end of 2018.

McCartin has now played 19 games and kicked 19 goals, but is yet to cement a spot for the Saints seven rounds into his third season.

He's been a sub, while concussion and shoulder injuries have limited his senior experience along the way.

The Saints clearly understand their player better than anyone, and are determined to make him earn his spot so he keeps it when elevated.

That's their prerogative.

But as long as McCartin continues to run around for Sandringham, the questions will keep being raised.