But Ellis is adamant that his Tigers team-mate will quickly put his disappointment behind him and concentrate on the end of the domestic season.
"We've got some massive games coming up in the Guinness Premiership play-offs and the semi-final of the Heineken Cup against Cardiff," added Ellis.
"Tom will have a huge role to play in these games and I know he will give 110% in each one of them.
"He's very mature, very professional and I'm sure his time will come for the Lions in the future."
Ellis started every game in England's Six Nations campaign and has been selected for the Lions ahead of more experienced scrum-halves such as Mike Blair and Dwayne Peel.
"It's been a real rollercoaster season for me this year, but I'm incredibly honoured to be named in a squad with such great players," said Ellis.
"I had seen my name being bandied around in the newspapers but wasn't sure what to expect. I must have impressed the selectors during the Six Nations and at club level.
I had seen my name being bandied around in the newspapers but wasn't sure what to expect
"It helps when you are playing with such great players week in and week out at Leicester, and the professionalism of the lads at the club is amazing.
"That has helped me of course but as I said there are a lot of important games left to come for Leicester this season and they are my immediate priority."
, 31, expects this to be his last Lions tour and knows of the task facing the side.
"South Africa have got some of the biggest physical specimens," he told BBC Radio 5 Live.
"I don't quite know what they give them but they seem to produce these massive 20 stone athletes that can sprint.
"It's almost the most physical battle you have in rugby against them. You have to relish it."
He added: "It's one of the biggest challenges in sport. We've got the best coaching staff and back-up team. Hopefully, the best players will all go now and stay injury free.
"But to get a team together for six games to take on the world champions in their own backyard is a huge task. The challenge ahead is enormous but an exciting one."
Worsley's Wasps team-mate Riki Flutey
is also in the squad and, if he plays, will be the first to play for and against the Lions.
"It's been an amazing year for me," he said. "Firstly being selected in the England squad and to now have been selected in the Lions tour is a huge honour and the pinnacle of my career.
"I played against the Lions when for the Wellington Lions when they toured New Zealand.
"I came on off the bench for Wellington and it was a special moment to play against the Lions and not in my wildest dreams did I ever think I would be representing them. But here I am being named in the squad and it's just fantastic.
"The Lions is an amazing sporting tradition and I'm just really excited to be a part of that."
The Lions depart on 24 May for a 10-match tour and play Test matches in Durban, Pretoria and Johannesburg.
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