ADELAIDE midfielder Hugh Greenwood has undergone foot surgery to correct Achilles soreness and won't return to full training until next year.

The 25-year-old basketball convert consulted a specialist and it was decided surgery, which he had on Monday morning, was the best way to correct the problem.

Crows general manager high performance Matt Hass said Greenwood would be reassessed after Christmas.

"Hugh was experiencing some soreness around his Achilles towards the back end of last season and it hadn't improved over the holiday period," Hass said.

"After further investigation, there was some irritation in an area adjacent to his Achilles and it was decided surgery was the best option for him.

"He will recover from the surgery over the next few weeks and build up to full training in the new year."

Greenwood was a revelation for the Crows this season after joining the club at the end of 2015 as a Category B rookie.

A former US college basketballer, Greenwood made his debut in the round nine victory against the Brisbane Lions at the Gabba.

He played 15 games for the Crows this year, but was rested for the round 23 clash with West Coast, and had only six disposals in the preliminary final victory against Geelong.

"That was an injury that happened during the season," Crows defender Jake Kelly told reporters on Monday.

"That was just a clean-out, they decided it wasn't worth going a whole year having that issue."

Kelly said he was surprised the surgery wasn't done immediately after the end of the season.

"Absolutely, but I don't know the thinking behind it," he said.

"He'll be back at Christmas time and he'll get a massive load in during the (JLT Community Series), so there won't be any issues."

Greenwood will face competition to keep his spot in the side with the Crows picking up Carlton star Bryce Gibbs and North Melbourne veteran Sam Gibson during the NAB AFL Trade Period. 

The Crows' first-to-fourth-year players were put through a punishing session in hot conditions at Thebarton Oval on Monday afternoon.

Riley Knight claimed the 2km time trial ahead of Wayne Milera, Kelly and rookie-listed big man Paul Hunter.

"Riley and Wayne Milera were very good today, they pipped me, but hopefully post-Christmas, I'll be in front of Riley," Kelly said.

After some ball drills, the players then finished off with a couple 1000m runs to ensure they capped off the first session of the pre-season in style.

The Crows are desperate to make amends for their Grand Final defeat to Richmond.

"We need to be more aggressive and in teams' faces," Kelly said.

"We need to be the aggressors.

"The Grand Final is the perfect example, when they came at us, Dustin Martin and those big bodies inside, we need to go, 'Nah, that's not going to happen'.

"We need to step up and start getting aggressive, like a Geelong/Sydney sort of model."

The remainder of the Crows' players will begin pre-season training on Monday, December 4.