St Kilda has been dealt an unfortunate double hamstring injury blow just over a month out from the season.

Channel Seven's Mark Stevens reports that midfielder Zak Jones is racing the clock to be fit for Round 1 after suffering a hamstring injury at training on Friday.

"A blow for Saints, with Zak Jones now borderline for Round 1 after suffering hamstring injury on Friday," Stevens tweeted.

Jones moved from Sydney to St Kilda ahead of the 2020 campaign and played 16 games in his first campaign at the club, averaging 19 disposals from 16 games.

Additionally, Saints youngster Ryan Byrnes could be sidelined for up to two months after sustaining a serious hamstring tendon injury at training.

The Age's Daniel Cherny reported the unfortunate setback, stating that the 19-year old will undergo surgery this week.

It will delay his start to the 2021 season - with the Saints opening their season against GWS on Sunday March 21.

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The club had just announced a contract extension for Byrnes that ties him to Moorabbin until the end of 2022.

The Sandringham Dragons product with was selected by St Kilda with Pick 52 in the 2019 AFL draft.

He made his AFL debut in Round 7 of last season and has played just the one game at senior level.

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St Kilda are expected to issue an injury update later on Tuesday - with Shaun McKernan (ankle) and Dan Hannebery (calf) also sustaining interrupted seasons.

The Saints face Carlton at Marvel Stadium on Thursday March 4 in their sole pre-season clash.