The Crows approached the AFL recently to clarify whether Jaidan Kappler and Brayden Maynard qualified to play for the club, given their fathers' lengthy careers in the South Australian league, but were told they could not sign either promising teenager.

While David Kappler played 290 games for South Adelaide, he did not play enough of them in time for Jaidan to be nominated by the Crows ahead of father-son bidding.

Under father-son rules, Adelaide has access to the sons of former Sturt, Glenelg, South Adelaide and Woodville-West Torrens players, provided they notched 200 games before 1990. They can also nominate the sons of Adelaide's own 100-game players.

Kappler would have become eligible had the AFL agreed to a Crows' proposal to include David's representative games in his tally, but the league was not agreeable.

Similarly, Peter Maynard, a premiership player and Hall of Famer at Glenelg after playing eight games for Melbourne in the early 1980s, did not play enough of his 200-plus games before the cut-off for Brayden to qualify, falling just four games short.

Jaidan Kappler is a tall, skinny midfielder in the mix to make South Australia's under-18 squad this season, while Brayden Maynard has made a promising start to the season playing for the Sandringham Dragons in the TAC Cup.

Adelaide protested to the AFL in 2006 after being told the club could not sign Gibbs as a third-round father-son pick because his father Ross had not played enough of his 250-plus games in what was then a 20-year qualification period running from 1970-1990.

The league acknowledged the club's concerns about the fairness of the father-son rule, abolishing the qualification period in favour of the simpler 1990 cut-off, but Gibbs went to Carlton as the No. 1 draft pick.

The Crows are also set to narrowly miss out on quick young midfield prospect Josh Koster, the son of premiership player Kym. Josh, whose father played in Adelaide's back-to-back premiership sides but retired on 95 games for the club, made South Australia's under-16 squad last year but is ineligible for this year's draft. Ben Jarman, the son of Darren, is available to both Hawthorn and the Crows and showed promise as a 15-year-old last year.

Will Paynter, whose father John played 198 games before the cut-off, missed out on being drafted a few years ago and is this season playing for the Crows' new reserves side.