ST KILDA defender Dylan Roberton is almost certain to miss the rest of the season – and has had a device implanted in his chest – as doctors monitor the cause of his irregular heartbeat.

Roberton, 26, collapsed on field during the Saints' round four loss to Geelong, but initially told reporters outside Epworth Hospital that he hoped to miss just one match.

But the father of three confirmed at Moorabbin on Thursday morning he would be out for an extended period, with doctors to track his heart for the next three months.

"There's rhythm problems going on in my heart – the electrical side of things – (and we're) still not sure as to why it happened, so I'll be out for the meantime," Roberton said.

"I probably won't get back again (to playing) this year, but I'm hoping at the end of this three months to get back to exercising and hopefully finish off the year back training with the boys.

"I've had a little device implanted in my chest, sort of like the size of a battery, which just feeds in what my heart's doing to the doctors and all their computers.

"They'll be able to pick up what's happening and then, with the testing, they'll be able to put all that information together and make a decision from there."

Roberton only became concerned he was dealing with something more serious once doctors continued to order more tests.

He found it "weird" and "pretty shocking" watching the vision of him collapsing on the news, but retains no memory of it actually happening.

"I feel fine, but still there's that hope it's just going to be fine and I'll be fine, whereas if there was a diagnosis that it was no good, that would be pretty hard to hear," he said.

"But I'm hoping everything's going to go well and with all this testing over the next three months I'll get the all-clear.

"I'm sure it's a possibility (I won't play again), but I've just got that hope I'll be back one day and I'm sure I will.

"Footy means a lot to me, but obviously being healthy and being there for my kids is the most important thing."

Roberton, who gave the playing group an update on his condition shortly before fronting the media, is permitted to do some light exercise during the next three months.

Coach Alan Richardson said Roberton, who is undertaking the Level 2 coaching course, would work with St Kilda's developing backmen in the meantime.

"Our priority (is) to make sure he's in really good shape," Richardson said.

"We're really hopeful, and to some extent optimistic, at the back end of this three months he gets the all-clear and … we take the whistle back and he puts his footy boots back on."