Giants defender Adam Kennedy will be sidelined for the next 4-5 months after undergoing a shoulder reconstruction.

The 28-year-old suffered a shoulder injury at training last week and is expected to return in the second half of the season.

Kennedy's setback is the second of its kind to riddle the Giants' pre-season preparations, with recruit Braydon Preuss facing a similar timeline after undergoing surgery last week.

“It’s really unfortunate for Adam but we know he’ll attack his rehabilitation with his usual diligence and professionalism," head of medical Cullan Ball said, per the club's website.

“He’ll rehab alongside Braydon who’s surgery went really well last week and he’s already back in at the club."

In a further blow to the Giants, forward Brent Daniels is expected to miss the opening rounds of the season after suffering a hamstring injury.

“Brent’s suffered a fairly significant hamstring injury so we’ll build him up slowly to be ready in the early parts of the season," Cullan added.

The Giants are preparing to face Sydney in a practice match this week at GIANTS Stadium with a number of key players set to miss the game.

Defender Phil Davis (knee), midfielder Lachie Whitfield (liver) and forward Bobby Hill (concussion) will all miss this Saturday's pre-season clash.

Captain Stephen Coniglio is expected to play this weekend in a return from concussion.