THE RETURN of Jack Sinclair to St Kilda's rookie list this week could see the Saints forced to make at least three chances to the side set to take on West Coast this Saturday.

The Saints have already ruled out Nick Riewoldt, and are likely to be without Jack Lonie after both were concussed against Adelaide last Saturday.

Nick not out for the count yet: Saints 

But they'll also need to find a replacement for Sinclair, who after playing every game this season, is headed back to rookie status with Seb Ross to return from a hamstring injury in the VFL.

"Jack has been terrific for us. He's really made an impact, and has been a real find for the first half of the year," football manager Jamie Cox told AFL.com.au.

"But rules are rules, and he was promoted onto the full list for Seb.

"Like most young people, they're pretty impatient and I suspect he's probably the same so he'll be disappointed for sure. But he's a smart kid, he understands the rules and knows what's got to happen.

"Truth be known, he's played more footy than he would have expected himself to have at this stage of the season. I reckon he'll be pleased with what he's done but also understanding that now he's just got to bide his time."

Sinclair was drafted by the Saints with the No.1 overall pick in last year's NAB AFL Rookie Draft.

After missing out on selection for the first NAB Challenge game against the Brisbane Lions, the former cricketer kicked a goal after starting as a substitute against Essendon.

He was then impressive against Hawthorn with 16 touches – eight in the first quarter – in a game where not much else went right for the Saints in a 106-point loss.

"He certainly came from deep in the pack," Cox said.

"He forced his way into the team and at that stage we had a lot of long-term injuries, which gave us the chance to promote him.

"He's really deserved his chance and hasn't let anyone down in the seven games he's played.

"He's been a real find and is a real footballer, and someone we're pretty excited about."

With the Saints' long-term injury outlook continuing to improve, Adam Schneider and Ahmed Saad face a similar fate in the next month.

The players they were upgraded for – Daniel Markworth and Arryn Siposs – are due back from shoulder operations around the bye week in round 12.  

Schneider has played six games and provided leadership in the forward line that missed Riewoldt from rounds three to five, while Saad played the first four games.

Meanwhile, a scheduled weekend off for Paddy McCartin and Hugh Goddard hasn't affected their chances of selection this week.

The recently-drafted duo, plus rookie Brenton Payne, were given a few days away from the club over round seven to freshen up.

With Riewoldt out, an opportunity for McCartin or Tim Membrey – who kicked three goals for Sandringham after being omitted last week – has opened up.

"They're all fine and will be back this week," Cox said.

"It's not as though they've been excluded from that [selection] discussion because they've had a week off.

"They're back now in full training to prepare for the week ahead."