CLAY Smith will have to deal with some mental "demons" as he recovers from his second knee reconstruction in a year, Western Bulldogs football manager Graham Lowe says.

Smith ruptured his right anterior cruciate ligament playing for the Bulldogs' VFL team last Sunday, having ruptured the same ligament in round 16 last year against Essendon.

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After undergoing a traditional knee reconstruction last July, the midfielder returned to the field just nine months later, in round two of the VFL this season.

He earned a recall to the Bulldogs' senior team in round 10 against Gold Coast, but injured an AC joint in that game which required surgery.

Lowe told SEN radio on Thursday he expected Smith to tackle the rehab from his second reconstruction in the same professional way he had approached his first.

"It's a frustrating time for the young man. He's done so much to get himself right after a very similar time last year, and obviously to reinjure his ACL again is really frustrating," Lowe said.

"There are some really positive signs about how he progressed last time to get himself back on the field.

"He was going really well and showing some really good form and we know he will do everything right to get himself back on the track again."

Lowe said it was inevitable Smith would have mental lows during his rehabilitation period.

"There's no doubt returning to the same injury can play a part. I think he's such a focused young man that he'll have his moments and no doubt he'll have his demons with that," Lowe said.

"He was so dedicated last time (and) our expectation is he'll do the same this time and get it right."

Fellow Bulldogs midfielder Mitch Wallis also suffered a season-ending injury last weekend, fracturing his left foot in the senior team’s narrow loss to Essendon.

Lowe said Wallis would have surgery to repair his foot on Saturday and was expected to be ready for the start of 2015 pre-season training.

"He's such a professional young fella and he spent a lot of time in the VFL and really built himself back up," Lowe said of Wallis, who was dropped from the Bulldogs' senior team after round five this year and did not return until round 11.

"He was playing some great footy for us.

"He's got surgery on Saturday, and again no doubt with him he's going to do everything right to get himself back onto the track in quick time."