Lions Head Coach Clive Woodward sees Thomas' leadership skills as central to the touring side's chances of over turning the odds against the All Blacks in the remaining two tests in the series.
"Gareth Thomas is an outstanding player and a natural leader" said Woodward.
"After Saturday's match we are going to need big characters out there who can dig deep and show real fight and courage.
"Gareth is such a character. We did not play as well as we could or should have but I am in no doubt we can beat New Zealand.
"Gareth's leadership will be central to meeting that challenge."
Following his return from New Zealand, Thomas can look forward to a challenging Heineken Cup season when Toulouse set out to defend their title in Pool 6. They will face Zurich Premiership and 2004 Heineken Champions London Wasps, as well as Llanelili Scarlets and Edinburgh Rugby.
Leinster centre Brian O'Driscoll suffered a dislocated left shoulder in the first 90 seconds of the test and was carried off in a stretcher. Indications are that he will be out of the game for several months.
Another Welsh Grand Slam winner, Ospreys forward Brent Cockbain has been called up to join the Lions squad as a replacement for the suspended Danny Grewcock.