Lever was selected by the Crows with pick No.14 at last Thursday’s national draft, after a year spent recovering from a knee reconstruction.
Although Modra is the club's all-time leading goalkicker, his No.6 guernsey has switched to the backline in recent years, with defender Luke Thompson wearing it before Lever – also a defender.
Left-footed defender Harrison Wigg will take No.35, which was vacated by Shaun McKernan, who joined Essendon at Wednesday morning's rookie draft.
Harry Dear has pounced on No.38, which became available when Mitch Grigg moved up to No.8, while Mitch McGovern chose to wear No.41.
Rookies Reilly O'Brien, Keenan Ramsey and Anthony Wilson will wear numbers 42, 43 and 46.
Twitter: @AFL_Harry