The best chance Wests Tigers have of ensuring Ivan Cleary's long term commitment is to convince Nathan Cleary to join the club, as a motivation for Ivan to consider returning to Penrith is to avoid coaching against his son.

While many have questioned why Cleary has seemed to be in a rush to coach Nathan given the 20-year-old is expected to have at least another decade in the NRL, those who have been in a similar position believe it would be difficult for Ivan to devise match plans aimed at nullifying his son's game.

Imagine Ivan, the father, having to tell Tigers props, such as Russell Packer and Ben Mautulino, to target his son.

Yet Ivan, the coach, would need to regard Nathan as merely the Panthers playmaker and instruct his forwards to run at the halfback to tire him out in defence, or apply pressure as he tries to get a kick away.

Former Cronulla, Penrith and South Sydney coach John Lang, who took the Panthers to the 2003 premiership, is the only other coach in recent memory whose son was a regular NRL player at the same time he was coaching.

Lang never coached against his son Martin, who played 176 NRL matches in the front row for Cronulla and Penrith, as well as eight State of Origins for Queensland, and he said it was not something he would have liked to do.

Penrith Panthers star Nathan Cleary. ©penrithpanthers.com.au

"With Martin, it wouldn't have been such a big issue because he was the type of player who just did his thing, but on balance I would have rather coached him than coached against him," Lang told pan66.com.

"With this situation with Nathan, particularly as he goes forward, if you are coaching against him he is the dominant playmaker in the opposition and you are running big blokes at him or working out ways to try and bring him down. It wouldn't be a good feeling."

There are other examples in Australian sport of fathers coaching their offspring, such as basketball's Lindsay and Andrew Gaze, football's Gary and Emily van Egmond and boxing's Tony and Anthony Mundine.

Shane Mosley, Roy Jones and Floyd Mayweather were all taught to box by their fathers but Mayweather is one of the few athletes whose father, Floyd Mayweather snr, trained a rival, Oscar De La Hoya, with the aim of beating his son in 2012.

Melbourne coach Craig Bellamy even found it difficult plotting against Storm stars Cameron Smith, Cooper Cronk and Billy Slater when he was guiding NSW and they were playing for Queensland.

"It wouldn't be a very good feeling, particularly with Nathan being a top playmaker, trying to work out ways to bring him down," Lang said.

"Neither way is probably ideal to be perfectly honest, but Ivan and Nathan are both in the same business so they have got no choice. Therefore, I think on balance it is more favourable to be coaching him than to be coaching against him."

With Ivan stating two weeks ago that he and Nathan wanted to work together after the playmaker comes off contract at the end of next season, Panthers GM of football Phil Gould made the stunning revelation he would not stand in the way of the Clearys reuniting.

What wasn't known at the time was that Penrith chairman Dave O'Neill had already discussed with Ivan the possibility of him returning to the club and potential legal action by the Tigers won't make Cleary stay and coach their team.

The Panthers are also trying to convince Nathan to commit to a new long term deal before rival clubs can commence negotiations with him at the end of the season.

Former Panthers, Cronulla and Queensland prop Martin Lang was coached by his father John. ©NRL Photos

Cleary told a media conference on Saturday that he intends to honour the remaining two years of his contract with the Tigers but reaffirmed his desire to coach Nathan at "some time" in the future.

However, Cleary's refusal to answer questions after reading a brief statement leaves open the possibility that he could sign with the Panthers from 2021, which would then leave the Tigers to decide whether they want him to remain as coach if he has committed to a rival club. 

While the Tigers can't table a deal to Nathan before November 1, there are no rules in the NRL stopping a club from approaching a rival coach at any stage of his contract but the Tigers may be able to place Ivan on "gardening leave" should that occur.

It is a tactic used in English football, with Cyrstal Palace putting manager Steve Bruce on gardening leave after he attempted to resign less than a year into his contract to join Birmingham City in 2001 without giving the required nine-month notice.

Reading took similar action against manager Alan Pardew when he sought to quit for West Ham in 2003 and forced him to sit out the game for a month while agreeing not to employ any of the club's staff or players as well as securing GBP380,000 in compensation.

What may be crucial in any legal case is whether there is a stated period of notice by either Cleary or the Tigers to terminate their contract and if so, how much notice is required.