SYDNEY coach John Longmire has confirmed that veteran Jarrad McVeigh is likely to miss at least the first two games of the season after suffering a calf injury.

However, Longmire is confident McVeigh will rebound well given his "immaculate pre-season".

McVeigh, who didn't play in last year's preliminary final win over Geelong because of a minor calf strain on his left leg, suffered a more significant tear on his opposite leg last week at training.

Swans football manager Tom Harley said on the club's website on Tuesday that McVeigh's problem was a grade two injury to a load-bearing part of the calf and included some damage to tendons.

Longmire told AFL.com.au that the 31-year-old veteran of 287 games was likely to miss at least the first two games of the season, but he was confident McVeigh could have a significant impact on the team's season when he returned, as he did in 2016. 

McVeigh missed the first three games of last year after his rehabilitation from off-season knee surgery took longer than expected, but averaged just over 20 possessions from 21 of a possible 23 games for the rest of the season, and was his usual steadying influence across half-back. 

"Obviously both he and the club would rather it hadn't gone," he said. 

"He'd had an immaculate pre-season with his attention to detail and his work with our physios and conditioning staff, to get his other calf as good as he could, and was training really well. 

"This has set him back but we know he'll do everything he can to get back to peak fitness. 

"Those challenges are always going to be there as you get older, but he's got an enormous amount of experience to draw upon. 

"He's a massive competitor, he's a real professional, and that gives him a chance, and sometimes all that blokes like that need is a chance."

The Swans start the season against Port Adelaide on March 25 before a Grand Final rematch against the Western Bulldogs at Etihad Stadium, with McVeigh, young star Isaac Heeney (glandular fever), Tom Papley (knee) and Gary Rohan (back) all likely to be unavailable.