The All Blacks certainly have recent experience of a succession of players in the same position falling over at a World Cup, and they want to prepare for every possibility. So Osborne will soak up the environment and, even if he never takes the field, be better placed should an SOS call eventually arrive.
The likelihood of such a call only increases with every opportunity lost to Jane during a frustratingly injury-plagued season. Jane will be assessed as the All Blacks assemble in Auckland this week but is unlikely to return to the field until the ITM Cup, which may leave him, like Osborne, World Cup injury cover at best.
"With Waisake out for three months and Cory still struggling with his injuries, we just wanted to make sure we had someone else who's been in the environment," All Blacks coach Steve Hansen said of Osborne's selection.
"If we ended up going to the World Cup and needing some outside players, and [Naholo and Jane] weren't available, then we'd have someone who's been here and feels comfortable. It was a bit of pre-planning, really."
Hansen insisted Jane still had a chance of a seat on the plane to England, with both his past credentials and undoubted pedigree under the high ball keeping him in the frame. But the coach remained wary of choosing a player who has found it impossible to remain healthy throughout the season.
"It's making it harder [to select him]," Hansen said. "Cory's problem is he's just been repeatedly injured this year, and [the World Cup] is a tournament that you don't really want to be taking high-risk athletes to, because once you lose them they're gone for the competition.
"He's got an opportunity because he's got good runs on the board from the past but we need to see him back out on the track at some stage for the Lions."
Nehe Milner-Skudder is another outside back Hansen wanted to see, having recovered from the rib injury that has so far kept him from playing in the Rugby Championship. Milner-Skudder is likely to make his All Black debut at some stage in the next two weeks but this World Cup still looks too soon for the 24-year-old.
After his performances so far in the international season, Charles Piutau appears to have joined Ben Smith and Julian Savea as a near-certainty to earn inclusion in the outside back quartet, with the versatility of several other All Blacks rendering a bolter in the position improbable.
"Sonny [Bill Williams] has definitely [played on the wing] and Malakai [Fekitoa] did it in the under-20s," Hansen said. "Israel can play on the wing ... [Beauden] Barrett and [Colin] Slade can play multiple positions, and Ben can play fullback or wing or midfield if we needed him to. So there's a little bit of versatility there."
All Black squad
Dane Coles, Hikawera Elliot, Keven Mealamu, Codie Taylor, Wyatt Crockett, Charlie Faumuina, Ben Franks, Owen Franks, Nepo Laulala, Joe Moody, Tony Woodcock, James Broadhurst, Brodie Retallick, Luke Romano, Jeremy Thrush, Sam Whitelock, Sam Cane, Jerome Kaino, Richie McCaw (captain), Liam Messam, Kieran Read, Matt Todd, Victor Vito, Tawera Kerr-Barlow, TJ Perenara, Aaron Smith, Beauden Barrett, Daniel Carter, Colin Slade, Lima Sopoaga, Ryan Crotty, Malakai Fekitoa, Ma'a Nonu, Conrad Smith, Sonny Bill Williams, Israel Dagg, Nehe Milner-Skudder, Patrick Osborne, Charles Piutau, Julian Savea, Ben Smith.
