Bielsa's Mascherano headache

PIURA, Peru, July 14 (Reuters) - Argentina midfielder Javier Mascherano will miss Saturday's Copa America quarter-final against hosts Peru and his absence is likely to provide a big headache for coach Marcelo Bielsa.

The River Plate player picked up a second yellow card in Tuesday's 4-2 win over Uruguay and is suspended from the match in Chiclayo.

Mascherano is only 20 and has played a mere five internationals but his work-rate, passing and tackling have quickly made him a fixture in the side and an excellent replacement for injury-plagued Juan Sebastian Veron.

'I feel bad,' Mascherano told reporters. 'I'm angry to miss a game like this but there's nothing I can do.'

Bielsa said that Mascherano would be difficult to replace.

'He's a player who adapts quickly to the instructions he's given and he can quickly change the way he plays on the field when he's asked,' said Bielsa.

'He's a very tactically disciplined player,' he added.

Mascherano declined to discuss his own performances.

'I'm not doing an individual analysis halfway through the championship. The important thing is that we're playing well and we want to keep going down the right track,' he said.

'I'm trying to learn more about my position and all the tactical movements which Bielsa teaches us.

'I'm very grateful to have the confidence of my team-mates and the coaching staff.'