Which is why news of Tom Rogic's recurring groin problem, which is preventing him from getting the game time with Melbourne Victory back in his homeland and may even have brought his season to a premature end, has caught the attention of the Hoops boss.
The 21-year-old midfielder was loaned to the Aussie side in January in an attempt to build the match fitness Rogic needs to ensure he is part of the Australian side which will head to the World Cup finals in Brazil this summer.
Former Rangers midfielder, Kevin Muscat - now in charge of the A-League club - fought off strong competition to secure Rogic on a short-term deal.
With Victory also included in the Asian Champions League - they are in the same section as Shunsuke Nakamura's Yokohama Marinos - the opportunity was there for Rogic to play regularly and at a decent level of competition.
Given how much time he spent frustrated on the sidelines since joining Celtic in January last year from Central Coastal Mariners, this was a much-needed chance to grab with both hands.
But Rogic's return to his homeland has brought, not re-ignition, but more disappointment as his lack of condition after so few games in the past year has left him susceptible to injury.
The current groin problem - which forced him to miss the recent trip to Yokohama, then, after a two-week rest, limp out of last weekend's game against Newcastle Jets - appears to be symptomatic of his situation.
Rogic wants to push on to prove his fitness and match sharpness, not least to Oz national coach Ange Postecoglou, who is in the process of finalsing his squad for the World Cup finals.
But, when he pushes himself too hard, something invariably gives and he ends up back in the role of unhappy spectator.
The Hoops boss is currently getting updated on the latest injury and said: "We get regular reports back on Tom's progress.
"Kevin Muscat was on the phone to me quite a lot during the January window. The people at Melbourne Victory are big admirers of Tom, obviously."
There were questions asked about the wisdom of allowing Rogic to travel back to Australia rather than to a Scottish or English club.
And, in hindsight, it has become clear that, had he stayed at Parkhead, the injuries to other midfielders, plus the early clinching of the championship would have meant he would have had game time at Celtic.
But, there are no regrets on the manager's part, and he explained: "Putting Tom out on loan to Melbourne was a chance to get games with the World Cup coming up.
"We felt, all in all, with him being back home as well, it would be more comfortable for him. But, Tom is still our player, and he will be coming back here."
By them, Lennon hopes to have watched Rogic strut the biggest stage of all where Australia are in a group with Spain, Holland and Chile.
"We might get to see him play in the World Cup as well, which would be fantastic," said the Parkhead boss, who hopes to be in Brazil.
"But, we already know what Tom has got. He has not really shown it consistently yet. But, maybe with the game time he has been getting in Australia, it will benefit him coming forward."
What Lennon wants everyone to keep in mind is that, despite his meteoric rise from a Nike scholarship to Central Coastal Mariners, to Celtic, and, hopefully, on to the World Cup as a rising star in the Aussie side, Rogic is still very much a novice.
Prior to joining Celtic, he had played only 27 senior games. Fifteen months on, that has risen by 34 - 15 with Celtic, 10 with Victory and nine for his country.
But Lennon considers him to be very much on a steep learning curve, one which he must negotiate for a good while to come.
But, Rogic is no lost cause, and Lennon is confident that, with vital experience under his belt, he will prove excellent value for the £400,000 Celtic paid.
"Tom found it difficult adapting to the pace of the game here at times," he said.
"In pre-season last year, he looked very good. But, when the season actually got going, we just felt he was still a yard off it.
"Maybe the more game time he gets, he will find that pace of the game."
Time, rather than game time, will tell.