Gerrard was included in England's starting line-up for the games against Israel and Russia last week and completed the latter. There was controversy before the qualification period as the midfielder suffered a broken a toe just weeks before.
"I might not be really happy to see my players going all around the world, playing 90 minutes in every game, but because you cannot change the situation you need to see how the player is afterwards and hopefully Stevie can play against Portsmouth," commented Benitez on Liverpool's official website .
"I was disappointed he played the full 90 minutes but we must have a lot of respect for managers and in this case I don' t want to say too much. I said congratulations to Stevie and congratulations to Steve McClaren and the country, but we knew it could be like this.
"We knew he was going with the national team and we needed to accept the situation. We need to analyse every player, because it is not the same for each one.
"It's not the same for a centre-back to play 90 minutes as it is for, say, a striker. It's also different if the player is playing for a team using an attacking game or a counter-attacking game.
"The physical demands are different and we analyse each one, talk with the doctor and talk with the fitness coach, Paco De Miguel, and make a decision.
"It's good for us to have so many players away because it means we have very good players, but it's bad because you would like to see them play some games, but not every game."