RIO DE JANEIRO, May 28 (Xinhua) -- Neymar had to leave his first full training session with Brazil half way ahead of the Copa America after the striker appeared to feel pain in his left knee on Tuesday.

The 27-year-old left the field in the Granja Comary training ground outside Rio de Janeiro alongside doctor Rodrigo Lasmar. Brazil's football confederation said Neymar had felt "discomfort" in his knee and was being evaluated by the medical staff.

It was another setback for Brazil's biggest star, who has only played four matches with Paris Saint-Germain since he returned from a broken metatarsal in his right foot on April 27.

That was the same injury that slowed his runs and dribbles at last year's World Cup.

Brazil fitness coach Fabio Mahseredjian had said before the training session that Neymar should be fully recovered after a pair of friendlies against Qatar and Honduras in early June.

But on Tuesday, which marked Brazil's first full training since players started gathering for the South American championship, Neymar had to leave and appeared to be in pain after taking a shot near the end of the session.

The Copa America starts on June 14 with host Brazil facing Bolivia in the opening match at Morumbi Stadium in Sao Paulo. Venezuela and Peru are also in the same group.

Brazil's coaching staff was also optimistic about Neymar's recovery for the World Cup in Russia, but the striker instead made news for his splashy dives rather than his once frequent dashing performances.

Neymar is also heading into the Copa America, a tournament Brazil hasn't won since 2007, with a disciplinary problem.