Lennon withdrew from last week's quarter-final first leg in the Spanish capital at the last minute due to illness.
The England winger missed Saturday's 3-2 Barclays Premier League victory over Stoke with the same problem, but looked sprightly this morning as he trained with the rest of the Spurs squad at their base at Chigwell, Essex.
Steven Pienaar also trained with the squad and could be set for a return from the groin injury which has troubled him recently.
Neither Vedran Corluka (ankle) nor Niko Kranjcar (foot) took part in the session, though, and both are doubtful as Spurs face the challenge of reaching the semi-finals after a crushing 4-0 defeat in the first leg at the Bernabeu.
Source: PA
Source: PA