Carlton young gun Charlie Curnow was encouraged to test his troublesome right knee before suffering the injury that has derailed the AFL forward's summer.
Curnow was playing basketball last month when he dislocated the knee and he has since undergone surgery.
But Blues coach David Teague says the club encouraged the 22-year-old to play and basketball and surf in the off-season.
Curnow did not play after round 15 because of an injury to the knee.
"Your initial reaction is disappointment - you don't want to see any of your players get injured," Teague said on Wednesday.
"In terms of what he did, I'm totally comfortable.
"We needed him to test his knee out, he hurt it at the end of (the season).
"Right now, sitting here, I'm happy he did it in October and didn't do it in December or January - that would have impacted him."
Curnow was on the sidelines on Wednesday as Carlton started pre-season training.
Teague is hopeful that Curnow, a solid trainer, will return quickly from the surgery.
"Charlie was riding the other day, which surprised me," Teague said
"He's in really good shape.
"So hopefully he'll be running before Christmas."
Eddie Betts, back at Carlton after six seasons with Adelaide, joined younger teammates at Wednesday morning's training.
Teague, who coached Betts at the Crows, had lobbied for the Blues to trade for him.
"I was keen - we were looking to add some small forward talent," Teague said.
"But Eddie brings so much more ... off-field, he brings a lot.
"He'll be a great leader for this football club and some of the older guys were (saying) 'yeah, get him back, we want him back'."
Overall the trade period was rated a bust for Carlton, who missed out on Jack Martin and Tom Papley.
But Carlton could still secure Martin in one of the drafts.
"We're still pretty keen to get him. It was disappointing," Teague said of the Gold Coast forward.
"At the end of November, we'll learn the fate then."
Teague also said that regardless of what happened in the trade period, he was bullish about his young team's 2020 prospects.
"I felt if we added no-one to our list, that we'd still improve," he said.
"I have complete belief in this group, that we're going to get better.
"If we don't get Jack Martin, I still think we're going to be a good team."
Co-captain Sam Docherty is visiting a knee specialist overseas as he returns from a second reconstruction to his left knee.