The England captain had been a favourite to tour and was even odds on to captain Warren Gatland's men at one point during the RBS 6 Nations.
But the flanker narrowly missed out on selection in arguably the most competitive position in the touring party.
Robshaw could not hide his disappointment but he is determined to take the positives from his omission.
"Of course it is tough," said Robshaw
"You think you are in with a good shout. I spoke to (Lions forwards coach) Graham Rowntree and he said I was close but that is not really a consolation is it?
"That is why the Lions is so special, it is so hard to be part of. You look at the competition in the back row, it is phenomenal the number of world class players.
"Unfortunately, I didn't quite make it. Graham was very honest with me. He didn't try and sugar-coat things. It is a setback but it is about how you react."
There is still a good chance that Robshaw will represent the Lions in Australia with history indicating there will be changes both before and during the tour.
In 2009, Sir Ian McGeechan was forced to make four changes, due to injuries and suspensions, prior to the tour and made a further four while in South Africa.
Four years earlier under Sir Clive Woodward there was one change made before the squad jetted Down Under and five while in New Zealand.
But Robshaw's immediate focus will by on Harlequins' bid to retain their Premiership crown, starting with Saturday's semi-final against Leicester.
"You have a little sulk but we are into a semi-final this weekend. It is about making sure we finish the season in the right way."