SYDNEY, AUSTRALIA - APRIL 24:  Wycliff Palu looks on during a Waratahs Super Rugby training session at Moore Park on April 24, 2012 in Sydney, Australia.  (Photo by Ryan Pierse/Getty Images)

It never rains but it pours … Wycliff Palu gets a soaking at Moore Park yesterday as the injury-hit Waratahs prepare for the Crusaders. Photo: Getty Images

THE Waratahs have been forced to look outside their 30-man squad to fill their depleted back line, with Sydney University's Peter Betham in line for a wing spot against the Crusaders in Sydney on Sunday.

The Waratahs players are not exactly brimming with confidence at the prospect of confronting last year's finalists and the most successful Super Rugby franchise, who may even have All Blacks captain Richie McCaw back on the reserves bench, when they are well short of fielding their best line-up.

Their back line looks most vulnerable, as they are looking for a fullback and outside centre after a shoulder injury to Bernard Foley and the two-week suspension of Rob Horne.

While Tom Kingston is likely to fill the outside-centre spot and Adam Ashley-Cooper expected to move to fullback, there are two wing spots to fill, prompting Betham's call-up.

The Waratahs management have been in contact with the Australian Rugby Union seeking permission for them to select Betham from outside the squad. The winger, who was with the Rebels last season, has been close to selection with the Waratahs for some weeks.

Betham and Atieli Pakalani ran on the wings yesterday in a disjointed training session at Moore Park, where the Waratahs were unable to run their proper back line because five-eighth Berrick Barnes had to leave early due to a stomach complaint.

The Waratahs will try again today, working on several back-line combinations before deciding what is the best mix to confront the Crusaders.

In between torrential showers, the news didn't get any brighter for the Waratahs when they were informed that McCaw was a possibility of appearing at Allianz Stadium.

Waratahs No.8 Wycliff Palu shook his head and started laughing. ''That's good for us, isn't it?'' Palu said. ''We always seem to get the Crusaders where everyone is back on deck. Whether he's starting or off the bench, we just know this will be an 80-minute game. It's too bad that he's not coming back the following week.''

Palu is a veteran of many battles with McCaw, both at Super Rugby and Bledisloe Cup level. ''I've played him a fair few times now. He's one of those players who is very hard to get to, and when you do actually get him, it doesn't really affect him.''

And then there's Kieran Read, for whom Palu has an enormous respect. When asked where Read sits on the international back-row pecking order, Palu said: ''He's right up the top. He does everything a back-rower should do. He jumps in the lineout, is a good scrummager and [is] good around the field as well.''

As for Ashley-Cooper, he is just waiting to find out where he will be playing - fullback, centre or wing. ''It is actually a very good question, he said.

''There is a possibility I play either 13 or 15, but it depends how the combinations work at training this week. We just have to see how we gel together before deciding on a back line to play the Crusaders.

''We have a few injuries, and we'll be up against it. But this team does perform well under pressure - and we're certainly feeling it this week. Still we know you can't get away with anything against the Crusaders.''

Meanwhile, former Wallaby No.8 Tim Gavin has been appointed NSW Rugby Union president, replacing John Coolican. Gavin was handed the position at the NSWRU's annual general meeting on Monday night. Mick Mathers was elected vice-president.