The door had appeared open for Hook after Rhys Priestland was ruled out of the tournament but Dan Biggar made the fly-half jersey his own and Jamie Roberts and Jon Davies remained centres of attention.
Hook played just 24 minutes during the campaign and while he was delighted to earn a third Six Nations winners' medal, he admits it was a relief to return to club rugby with Perpignan.
"It's always frustrating sitting on the bench and not playing," said Hook.
"It wasn't an ideal campaign for me but I will still part of a squad that won the Six Nations.
"The celebrations after England were a bit bittersweet for me. I was obviously thrilled for the boys, I saw how hard they all worked and the effort put in, and it was nice to get on in the last couple of minutes to feel a bit more of a part of it.
"But I'm just happy to be back playing regular rugby. This is a place where I love playing and it's nice to be back on the pitch.
While Hook had limited opportunities to remind Gatland of his capabilities during the Six Nations, the Lions head coach will be keeping a close eye on the knockout stages of Europe.
Hook was instrumental in Perpignan's 30-19 Amlin Challenge Cup quarter-final victory over Toulouse on Friday night- setting up two tries and kicking 15 points in an imperious display.
The Catalonian giants return to Top14 action before facing Stade Francais in the semi-finals - the last round of games before Gatland names his squad.
"Overall we are delighted with the win," added Hook.
"We have put a big focus on this competition and it was a big test against Toulouse.
"We had to dig deep in certain parts but it was great to get the result which puts us in the semi-finals.
"A big turning point was at those scrums after Dan Leo was sent-off. We were on our own line and if they had scored it might have been a different story.
"But it was a great effort from the boys, especially in those last 15 minutes with 14 men.
"I was also happy with my own performance. My kicking and running games were pretty good and I just want to build in this."
Gatland has already indicated that he will take just two fly-halves to Australia and Jonny Sexton, Owen Farrell and Dan Biggar appear the leading candidates.
But the Lions will also need other players that can slot into the number 10 jersey and Hook's versatility, with the ability to play 10, 12, 13 and 15, could be crucial
"I'm confident I could do a job for the Lions. I went in 2009 - I loved it then and I would love to go again but it's not my decision," added Hook.
"I don't know if it will help me but obviously I can play in those other positions.
"All I can do is focus on Perpignan, make sure I play well here and see what happens. I genuinely want to do well here - for the club, my family and myself."