Croft toured with the Lions four years ago but was a doubt for this year's squad after breaking his neck and spending eight months out of the game, only making his comeback for the Tigers in January.
"When I got injured I was just hoping to get back and playing and I was very fortunate to be involved at the end of the Six Nations,'' Croft said. "My train of thought was getting on to the England tour of Argentina. That would have been a massive bonus and a highlight for me so being included in the Lions squad has far surpassed that.''
Leicester are the best represented club with six players in the form of Ben Youngs and his brother Tom, Dan Cole, Geoff Parling, Croft and Manu Tuilagi.