UEFA.com reports: Champions League debut and first goal, the Del Horno ban, the 2006 thigh injury, and the Spanish passport
UEFA · 2005
Governing-body reporting. UEFA used both "hamstring" and "thigh" for the March 2006 injury, and contemporaneously reported that Messi "juro la Constitucion". No URL survives in the corrections addendum, so this source is not recorded as fully retrieved.