(Reuters) - Defender Pablo Zabaleta is injured and will miss Manchester City's Premier League clash against Southampton on Sunday, leaving manager Pep Guardiola with a selection dilemma as the club's other recognized right back Bacary Sagna is also injured.

Zabaleta injured his foot in City's 4-0 Champions League defeat at Barcelona on Wednesday.

Guardiola said the Argentine would be back in time for Wednesday's League Cup fourth round match against Manchester United, although the hamstrung Sagna will be out for at least another two weeks.

Guardiola defended his selection policy in Europe at a news conference on Friday, rejecting media reports that striker Sergio Aguero and defender Vincent Kompany do not feature in his plans this season.

Aguero, the league leaders' top scorer, was left out of the starting 11 against Barca, while Kompany, the club captain, did not make the match day squad.

"On Sergio, I said after the game it was a tactical decision," Guardiola told reporters. "I wanted one more midfielder, I tried to keep the ball in the Camp Nou and when you have the ball, Lionel Messi, Neymar and Luis Suarez don't."

"I thought in the last 30 minutes, with the Barcelona center-halves tiring, he could help a lot from the bench. When Sergio decides to leave Manchester City it will be his decision. Next time before you (the media) decide he is not in my plans, you can call me."

Guardiola confirmed a lack of fitness was the reason behind Kompany's absence.

(Reporting by Ian Rodricks in Bengaluru; editing by Martyn Herman)