GEELONG captain Joel Selwood will train on a modified program before Christmas as the Cats continue to manage his ageing body.

The skipper, who turns 31 in May, was barely sighted on the track last week as his senior teammates returned to training with two punishing running sessions at Deakin University.

Having sat out blocks of running last year while recovering from a serious foot injury, Selwood said the modified loads in his 13th AFL pre-season were due to his age.

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"Mine's probably a bit of a slower build compared to the others," Selwood told  

"It's mainly just an age thing more than anything else, I'll only be in parts of training leading into Christmas. After that I'll be with the boys for most of it."

"It's simply that I'm 30 years of age now and just have to be more careful with the body and prepare it in the right way."

Selwood, who averages 22.6 games a season across his career, was the most notable absentee as the senior Cats returned to duty, two weeks after their younger teammates.

Gary Ablett (34), Harry Taylor (32) and Tom Hawkins (30) all took part in large chunks of running before they sat out the final 15 minutes of conditioning during Friday's session.

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Zach Tuohy is expected to return to full running in coming weeks after knee surgery.

Contracted until the end of 2021, a year in which he will turn 33, Selwood praised a AFL-wide approach where senior players were given extra allowances during pre-season.

"The league is getting better at it, wanting to see players around longer," Selwood said.

"It's great to see Luke Hodge and 'Sandi' (Aaron Sandilands) and the older guys going around because they really still are great footballers.

"We've got to make sure we keep them around as long as we can."

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Much like superstar teammate Patrick Dangerfield, Selwood put the heat on his younger teammates to force their way into key midfield slots in 2019.

With Selwood, his brother Scott (29), Ablett (35), Mitch Duncan (28), Sam Menegola (27), Cameron Guthrie (27) and Dangerfield (29) part of an ageing midfield, the Cats are desperate for the next wave to come through.

"I've always been on the case that you never want to anyone to give up a spot. Now I'm in that position where I'm not going to give up my spot," Selwood said.

"There's other proud players at this club that aren't, and these kids have got to come and take them off us.

"We'll make sure we're around with them and have that healthy competition within the club that will make us the best we can be."

After holding on to 24-year-old Tim Kelly despite his wish to be traded to West Coast, the Cats are searching for fellow youngsters to follow his lead.

The next batch includes Brandan Parfitt, Nakia Cockatoo, Jordan Cunico, Lachie Fogarty, Quinton Narkle and the untried Charlie Constable, all of whom will be all 23 or younger by next September.