LUCKLESS St Kilda forward Paddy McCartin has experienced fogginess and nausea after suffering whiplash against Melbourne last Sunday afternoon, and faces yet another stint on the sidelines.

McCartin will miss Saturday's match with Fremantle on Saturday at Optus Stadium, and the Saints are yet to provide a timeline on when the 22-year-old will return.

The No.1 selection from the 2014 NAB AFL Draft clashed heads with Neville Jetta against the Demons and had a concussion test, but was passed fit. A later incident with James Harmes saw him suffer whiplash.

While McCartin's neck has recovered from that incident, his other issues mean he will miss this weekend.

"The first knock was fine and he passed the concussion test. The second knock left him feeling a bit nauseous and a bit of a foggy feeling and given it was late in the game, we took a conservative approach," St Kilda head physiotherapist Andrew Wallis told saints.com.au.

"With travel to Perth, he'll miss this week, and then we'll update fans later."

McCartin had strung together seven consecutive games to start the season – the longest streak of his 29-match career.

Promising small forward Ben Long could be out for the next three months with a right foot injury.

"Ben Long has got a stress fracture in his foot, so he'll miss probably 10-12 (weeks). He'll be in a boot for about 4-6," Wallis said.

In positive news for the struggling Saints, Josh Bruce has completed two running sessions and is feeling no pain in his lower back after suffering from bone stress.

He is expected to miss another four weeks.

Darren Minchington will spend another fortnight recovering from his left knee injury. After having made his way through two one-on-one skill sessions, Minchington will resume training with the main group.