[3] In late 2012, Lever received a scholarship with the Australian Institute of Sport (AIS) when he was named in the AIS/AFL Academy level one squad as part of their 2013 intake.

[5] He played fourteen matches for the season, including the preliminary final loss to the Dandenong Stingrays,[6] and finished third in the best and fairest count.

[10] In November 2013, as part of academy training, he jarred his knee which scans later revealed he had torn his anterior cruciate ligament (ACL).

[12] Despite missing the entire season due to the knee injury, he was still being touted as a top ten draft pick and was described by AFL Media journalist, Callum Twomey, as a "competitive and aggressive tall defender who can shut down opponents while also providing good rebound...his leadership is excellent as is his work rate and feel for the game.

He started the sport in year seven to stay fit during the football off-season and had planned to participate in amateur fights during 2014, but was unable to due to his knee injury.

[20] After playing in a handful of matches in the SANFL, his form was publicly praised by then-Adelaide coach, Phil Walsh,[21] and he was named to make his AFL debut in round six against Gold Coast at Metricon Stadium.

[1] In his fourth match, he recorded seventeen disposals and five marks in the eleven point loss to Fremantle at the Adelaide Oval in round nine and was named in the AFL Media's team of the week.

[27] He was highly praised for his performance in the match by Adelaide's caretaker coach, Scott Camporeale, who said "he's a great competitor...he's going to be a 200-game player of this footy club and a real leader.

[36] His continual growth in defence drew public approval from the media including The Advertiser's journalists, Scott Walsh and Reece Romfray, with the former highlighting his "ability to read, and squash, opposition entries to the forward 50" and the latter stating he was the "captain in waiting" for Adelaide.

[38] He earned AFL Media team of the week honours for the sixty point win against Carlton at the Melbourne Cricket Ground in round sixteen.

[58] Labelled the best young key defender in the league by former Melbourne captain, Garry Lyon,[59] Lever was named the next Alex Rance—a four time All-Australian defender—by Riley Beveridge,[60] due to his intercept marking and ability to read the play.

[63] Lever indicated early in the season he planned on signing another contract with Adelaide,[64] but was waiting until the collective bargaining agreement was finalised between the AFL and AFLPA.

[67] With his strong form during the season, journalists stated that his price tag would continue to rise[68][69] and Victorian clubs, Collingwood, Melbourne and the Western Bulldogs, publicly announced their interest in signing him.