A lingering knee ligament injury looked to have scuppered Cummins chances after he was forced to miss seven Super XV games but Deans has seen enough of the 25-year-old winger to hand him the opportunity of a lifetime.
"I was shocked. But I'm happy and keen to get amongst it," said Cummins, who only made his international debut in October last year.
"My old man woke me up in the morning. He was going off like a bag of cats. He was happy with the news.
"I was in year eight when I first saw a Lions game. It's a pretty big deal.
"Even big Sharpie (Nathan Sharpe) hasn't done it, and he's done everything else known to man.
"If I end up getting a gig, I'll be going off like a cut snake. It would be something I would be able to cherish."
Cummins shot to prominence after a horrific injury list led to a Rugby Championship call up against Argentina in Rosario.
The man nicknamed The Honey Badger in reference to his ferocious defence showed his class in comfortably making the step up to Test-match rugby as he featured in the last six internationals of the year.
His team's solitary try scorer in the wins over England and Italy, Cummins has beaten off the challenge of veteran wing Drew Mitchell and the likes of Dom Shipperley, Henry Speight and Cooper Vuna to join Digby Ioane and Joe Tomane as the only out and out widemen in Dean's party.
James O'Connor, Adam Ashley-Cooper and Israel Folau can also play on the wing but are more often employed at full back, centre and fly-half respectively.