ST KILDA key defender Dougal Howard will miss at least the first month of the season after straining his hamstring in Sunday's AAMI Community Series win over North Melbourne, while young gun Mattaes Phillipou is dealing with a hip issue ahead of round one.

Howard exited the practice match at RSEA Park late in the fourth quarter after clutching his left hamstring, with subsequent scans confirming a hamstring strain that will sideline him for up to six weeks.

The 27-year-old missed the final five rounds of last year's home and away season after breaking his wrist and didn't return for the elimination final against Greater Western Sydney despite being fit, with Zaine Cordy retaining his spot.

With Coleman Medallists Jeremy Cameron and Tom Hawkins waiting at GMHBA Stadium on March 16 when the Cats open the Joel Selwood Stand, Ross Lyon will have to deal without not only Howard but Jimmy Webster, who is facing a lengthy ban for a crude bump on North Melbourne co-captain Jy Simpkin.

Webster was sent straight to the AFL Tribunal as expected on Monday after the MRO graded the incident as careless conduct, severe impact and high contact

Phillipou sat out the second half of Sunday's win over the Kangaroos due to hip soreness and will undergo treatment across the next fortnight. 

The South Australian is expected to be available for the trip down the highway.

St Kilda could start the season without a third defender, with two-time Trevor Barker Award winner Jack Sinclair facing a race against the clock to be fit for round one. 

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The star half-back, who has been named All-Australian in each of the past two seasons, didn't feature in the Saints' practice matches against Essendon and the Kangaroos due to a lingering calf complaint but is expected to return to the main group later this week. 

Josh Battle didn't play on Sunday after copping a knock to his knee in the match simulation against the Bombers, but the versatile defender will be available against the Cats. 

Cordy should replace Howard in defence after playing the final minutes of the game on Sunday, following 14 appearances in his first season at Moorabbin.

Draftee Arie Schoenmaker collected 16 disposals and 11 marks against the Kangaroos in his first appearance in red, white and black. 

Riley Bonner has catapulted himself into round one contention over the past fortnight, just four months after being handed a lifeline via the Pre-Season Draft after being delisted by Port Adelaide in September. 

The half-back amassed a game-high 30 disposals, seven inside 50s, six rebound 50s, 727m gained and a goal on Sunday to all but cement a spot against Geelong.