Both key players were left behind when the squad flew out on Sunday to China for a mini-tour of the Far East.
Gerrard is continuing his rehabilitation from groin surgery which ended his campaign in mid-March while Reina had a double hernia operation last month.
"Steven is injured at the moment and that's why he's not here with us," said Dalglish at a press conference after landing in Guangzhou, where the team will play their first friendly in China on Wednesday.
"He has made a fantastic recovery from his operation towards the end of last season.
"He just needs to get the final couple of niggles out of the way and then he will be fit for the start of the season against Sunderland.
"I know people are disappointed he isn't here with us but the disappointment would be far greater if he couldn't play the first (Premier League) game.
"That is why he has stayed at home, to rest and to have the best chance of being fit for the start of the season.
"The same situation applies to Pepe (Reina) - he had a double hernia operation in June.
"He isn't fit and so had to stay at home. He should be ready for the start of the season."
Liverpool's new signing Charlie Adam made the trip to the Far East, having sealed his move from Blackpool on Thursday, but Jordan Henderson, who moved from Sunderland last month, has been on extended leave after playing for England Under-21s at the European Championships in Denmark.
The Reds have been linked with a renewed bid for Aston Villa winger Stewart Downing while a number of fringe players are likely to be offloaded before the start of the new season.
"We are happy with the business we have done so far," added Dalglish.
"Hopefully we will do some more business before the window closes but I'm not going to give names because that's disrespectful.
"We are looking to bring other players in and that could mean we expect some to leave.
"That's football but we have a while to go yet and we'll see what we can do."