ST KILDA defender Dylan Roberton is feeling alert and well and is hopeful of missing just one week as he continues to undergo testing for an irregular heartbeat that prompted his on-field collapse against Geelong.

Roberton sparked concern among his teammates and the wider football community when he fell to the ground in the second term of the loss to the Cats. The father of three later reported dizziness and having a blackout.

The 26-year-old was sent to Epworth Hospital while the game was still in progress and was released on Monday. He hopes to miss only the clash with Greater Western Sydney this Saturday at Etihad Stadium.

"This week I'm ruled out, just as a precaution. I'll do all the testing and then hopefully, back on the track next week," Roberton told reporters outside Epworth Hospital on Monday.

Despite the worrying scenes, Roberton wasn't overly concerned.

"It was a bit of a scare, probably more so for family and friends. I was fine straight away," Roberton said.

He will undergo more tests in Melbourne this week, including an MRI, and has seen the incident only a couple of times as his phone has run out of battery. He didn't bring his charger, not expecting to stay in Geelong for so long.

Roberton's recollection of the incident is hazy.

"I just remember watching the ball go up and getting dizzy but that's about it," Roberton said.

Football manager Simon Lethlean predicted the backman's lay-off could be slightly longer when speaking to reporters at Moorabbin on Monday.

"In the short-term, he'll have a number of different tests and each of those results will dictate where he goes thereafter," Lethlean said.

"There'll be no exercising in the meantime, so at least a one or two-week lay-off and we'll see how it is."

Like most clubs, Saints players take wellness surveys twice a week and Roberton had not given medical staff any reason for concern.

"There's been no signs that this was coming. Hopefully it's a one-off event and we don't see it again, but nothing would have led us into thinking this might be occurring," Lethlean said. 

Coach Alan Richardson visited Roberton on Sunday night after the clash against the Cats. The backman was feeling well and in the immediate aftermath of the incident, he was not overly concerned.

"He's a pretty relaxed character, Dylan, so I think he headed off the ground and told a few that he was feeling a bit dazed and bleary-eyed. You don't get much more from Dylan about that sort of stuff," Lethlean said. 

"He's a pretty casual, professional guy and I think he'll deal with it accordingly."

Richardson said on Sunday that Roberton's teammates were "anxious" to learn of his wellbeing at half-time after he left the ground in the second term.

"From all reports he's alert, he's eating, certainly for the family members that are home, from all reports at the moment he's doing well," Richardson said post-game.

"One of the line coaches in particular, (backline coach) Henry Playfair, let me know the backs are really anxious and just want to know about one of their mates (at half-time). It was pretty important we got that information to them."

SAINTS GO DOWN: Full match coverage and stats

Concerned Saints players rushed to Roberton after he fell before the 26-year-old regained his feet after being assisted by two trainers.

He was able to walk unaided to the interchange bench where he was checked and then taken to the rooms and later hospital.

"It was obviously a bit of a shock, shocked a few of his mates," Richardson said.

"I've never really seen anything like that, my thoughts immediately go towards the player.

WATCH: Alan Richardson's full post-match media conference

"You're trying to get feedback reasonably quickly and there's not a lot of answers come back your way particularly when he goes off to hospital.

"It was really comforting once we were able to get some feedback that he's OK now."

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Geelong coach Chris Scott shared Richardson's concerns for Roberton, a player he had previously coached in his time as an assistant coach with Fremantle.

"It wasn't good. We actually saw it live. It's not often you're talking to your bench about getting our doctor out there to an opposition player," Scott said.

"It looked terrible and, knowing Dylan personally having coached him at Fremantle, adds another dimension to it.

"It was very concerning and I think you could see the players reacted too.

"They thought there was going to be a big hold-up in play and I was surprised he came off so quickly because it looked ugly.

"The St Kilda guys had it covered and it was more that someone got out to him really quickly if time was the essence and it appeared to us that it was."

The Saints were reduced to two players on the bench in the second half with forward Rowan Marshall ruled out with concussion suffered from friendly fire with teammate Jack Billings.

WATCH: Friendly fire concusses Marshall