ST KILDA might be required to choose between the heart and the head when it comes to a replacement for sacked senior coach Scott Watters.

Tugging at the heartstrings would be a chance to bring dual Brownlow medalist and club record games holder Robert Harvey back to the club from Collingwood, where he is the senior assistant to Nathan Buckley.

The more calculated choice might be Mark Williams, Port Adelaide's 2004 premiership coach and now in charge of player development at Richmond.

Harvey's return to St Kilda would be as emotional for Saints fans as was James Hird's ascension to the senior job at Essendon in 2011.

Timeline: from Lyon to Watters

Recently elevated to the position as Buckley's right-hand man, Harvey played 383 games for the Saints before retiring at the end of 2008. He immediately joined Carlton and spent two years under Brett Ratten before rejoining the Saints in 2011 for a year under Ross Lyon.

When Watters won the Saints' senior job in 2012, Harvey decided his coaching apprenticeship would best be served elsewhere and ironically, he joined the Pies as the replacement for Watters.

He has earned rave reviews for his work with the Collingwood midfield and is credited with taking the games of Dane Swan and Scott Pendlebury to a new level.

Williams worked with Greater Western Sydney for three years after leaving Port Adelaide late in 2009, but left the club when he missed out on the job to replace Kevin Sheedy.

He plays a big role at Richmond in development and as the boundary line coach on match days, but is itching for another crack at becoming a senior coach and moved his family to Melbourne after leaving the Giants, rather than back to Adelaide, specifically for such an opportunity.

He is on record as saying he believes he will be a better senior coach the second time around. Given he won 55 per cent of his 274 matches as coach of Port Adelaide, that makes him a tantalising proposition for the Saints.

Both Harvey and Williams would presumably have clauses in their contracts that allow them to depart their jobs immediately for what is seen as a promotion. However a more complicated arrangement, which has also been mooted, is Williams taking over with Harvey as his nominated heir apparent.

The Magpies might not necessarily release Harvey back to the Saints if that was the case.

Richmond football director Dan Richardson said the club had yet to learn of any interest in Williams from St Kilda.

"If they have any interest in Mark we have yet to hear from them, so we'll wait until then before taking it any further," he said.

"It would be premature to discuss it any further."

The Tigers had previously indicated to Williams it would not stand in his way if he was offered the Melbourne coaching job that ended up being won by Paul Roos.