The first is the high-profile Stars, after three years of semi-final exits, are under major pressure to deliver at least a Champions League berth and must do whatever it takes to achieve that.

The second is that Muirhead is the latest in a long line of wrist-spin bowlers, especially those in the first half of their careers, grappling with the cricket equivalent of a golfer with the yips.

In the space of a month, just before Christmas last year, Muirhead went from not having a Big Bash League contract to, after just two BBL matches as an injury replacement player and a few handy tour-match performances against England, being selected for his Twenty20 international debut for Australia.

Impressing in those three matches against England earned him a berth at the World Twenty20 in Bangladesh and prompted Victoria to give him a four-year domestic contract. His first, and only, match for them thereafter was memorable for the wrong reasons: 0-61 from seven overs away to NSW in the Sheffield Shield.

In the four months before he turned 21 in July Muirhead received personal tutelage from cricket's two most decorated spin bowlers, Shane Warne and Muthiah Muralidaran, as part of the Australian team and Cricket Australia's National Performance Squad, with the latter having a training stint in Sri Lanka during the Australian winter.

The first significant sign that Muirhead's positive career trajectory had stalled came in the mid-year quad-series in Darwin involving the performance squad with the "A" teams of Australia, South Africa and India. His series record of four wickets at 34.28 and 7.05 runs an over was the most expensive of any bowler in the series who featured in more than one match.

With Jon Holland and Fawad Ahmed ahead of him in the Victorian Matador Cup pecking order – he has yet to make his one-day debut for the Bushrangers – Muirhead's first match beyond club level was a Futures League match in Perth that conceded  almost seven runs an over in the second innings as the returning Shaun Marsh dominated for the Warriors.

A Twenty20 cameo of 3-25 from four overs for a CA XI against South Africa three weeks ago, plus 5-18 in Premier Cricket a month ago, were conspicuous high points for Muirhead. Beyond those he has habitually conceded more than five runs an over for St Kilda, enough to persuade Victorian selectors to discount him from Futures League and Second XI matches for fear it could do his already challenged morale more harm than good.

Even though Muirhead's three-year contract extension with the Stars was confirmed less than two months ago his form drop since has been significant enough that, had he not moved to the Scorchers, he could have been a benchwarmer behind Clive Rose for the entire season.

While Muirhead and Beer are both bracketed as spin bowlers they could hardly be more different. While right-armer Muirhead can achieve sharp turn, the sideways movement from left-armer Beer is often negligible. Where the 30-year-old trumps not only Muirhead but most of his peers is his ability to withstand the toughest period: the powerplay overs with restricted outfields.

In all but seven of the 24 times Beer has bowled in the BBL it has been with the new ball, which makes his career economy rate of 6.34 runs per over so impressive. The Stars are this year without powerplay expert Lasith Malinga and while Beer is not a patch on the Sri Lankan as a wicket-taking threat he is his comparable to him for stingy bowling.

When the Bushrangers gave Muirhead a four-year deal in February a large part of its motivation was an expectation that, despite his Twenty20 international debut, he had a long way to go before he could consistently command a shield spot. While Shipperd is at the helm of both the Bushrangers and the Stars the leg-spinner's departure from the latter should not cloud his future with the former.

The hierarchy's hope is that a short stint in a new environment may rekindle his confidence.

Leg-spinners can sometimes roar back into form as quickly as they plummet out of it and at 21 he most definitely has time on his side. If he can regain his confidence during the coming BBL, perhaps in tandem with Brad Hogg, the trade could be the win-win type often heralded in AFL.