Warren Gatland said the likes of James Haskell must be ready for a British and Irish Lions call-up despite being snubbed for the tour of New Zealand.
Haskell admitted he had come to the conclusion that he "wasn't meant to be a Lion" after the England flanker was omitted from a 41-man squad named last month.
Yet with the domestic season still in progress and such a demanding tour schedule to contend with, there is a strong chance Gatland will need to call for reinforcements.
And the Lions coach said those who get the nod must be prepared if and when they are needed.
"I think everyone, you keep your fingers crossed, if you're a player that's missed out and you know you're pretty close, your chance of getting in is if someone picks up an injury over the next month or early on in the tour," Gatland told Sky Sports.
"You might be disappointed now, but something can happen and change over the next two-three, six to eight weeks. You've got to be ready for a potential call-up if called upon."
That could provide some encouragement for Wasps forward Haskell, who conceded defeat in his bid to become a Lion.
"The Lions is the pinnacle of every rugby player's career. It's the difference between being a good player and a great player and I obviously wasn't good enough to do it. That's the fact," Haskell was quoted as saying by The Guardian.
"It was not to be really and there's nothing I can do about it. I've tried my best, but I wasn't meant to be a Lion.
"I thought I played well in the Six Nations and put myself out there. Could I have done any more? Not really. I just wasn't good enough in [the coaches'] eyes.
"There are obviously personal preferences and I wasn't the man to take it on. Excuses might give you comfort at night, but it's down to facts. I was disappointed, went home, spoke to my missus, it was like 'oh, that's s***', and then I went away and thought about it, but I'm done with it now.
"Ireland v England had a massive role to play in it; Peter O'Mahony played his way in. Ross Moriarty played his way in during Wales v England. It's about peaking at the right time and seizing your opportunity. I obviously failed to do that."