Defender Nick Smith will need to prove his fitness ahead of Saturday’s clash with St Kilda at the SCG after missing last weekend’s win over Port Adelaide with back soreness.

Smith, who had played every match for the season up until Saturday night’s clash, was a late withdrawal after pulling up sore on Friday, and failing to improve in time for the match.

Speaking to SwansTV for the HCF Injury Update, club physiotherapist Matt Cameron said the club gave Smith every possible chance to play, but had to withdraw the defender at the last minute.

“One of the discs in his back was a little bit suspect and he’s had a little bit of minor symptoms on and off throughout the year,” he said.

“He had a flare-up the night before the game and on the morning of the game, and we worked on him, but we just felt it wasn’t quite right so he withdrew from the game.”

Smith ran laps and completed some minor drills in Tuesday afternoon’s session at the SCG, and is expected take part in the club’s final session on Thursday morning.

Cameron confirmed that if Smith made it through Thursday’s training session, he would be cleared to play.

“He has improved quite a lot and we’ll have him running today,” he said.

“We’re expecting him to pull up well from that and train.

“If he can train, we’ll let him play the game, but if he can’t train, then we’ll have to have a re-think.”

Rookie midfielder Dan Robinson will also be assessed this week after missing the Swans reserves’ win over the Gold Coast Suns reserves on Saturday morning.

Cameron said Robinson, who sustained a groin injury early last week, would face a test on Thursday.

“Dan sustained a strain to one of his groin muscles last week and he was still reasonably sore by the end of the week, so he wasn’t able to play,” he said.

“He’s looking a lot better this week seven days later and we’ll put him through his paces this week and if he’s able to train then he’ll play on the weekend.”

In other injury news, ruckman Tom Derickx is taking time away from the club after being placed on the long-term injury list with a hamstring injury.

Cameron confirmed that Derickx required at least six weeks on the sidelines with the injury, which effectively put an end to his 2014 season.

“Tom has an unusual injury, but it came about after he just jumped at training, it wasn’t even a really high intensity effort,” he said.

“One of the hamstring tendons at his knee level ruptured off the bone.

“Whilst he wasn’t too debilitated with it, we gave it a couple of weeks for it to settle down and we tried to see if we could get something out of this season for him, but his knee and the bottom of his hamstring got sore again.

“Really, what that tells us is that the tendon is going to need a longer period of time to mend, probably in the region of six weeks and that effectively means no running or training, which is really right into September.”