Wales play their first international in Swansea for 17 years tonight - a match which could be seen as a dress rehearsal for the arrival of England at the Millennium Stadium on 3September for a World Cup qualifier.
But Toshack insists he does not want to be "blinded by the England match".
The 56-year-old said: "I can't let one or two particular games, when the result is not that important, stand in the way of the preparation we have to make. I hope that translates right, but I can't have the brakes put on what we are doing.
"Regarding England, I have not got a clue what team we will put out. But this Slovenia game is not a dress rehearsal for England, we are looking further ahead than that.
"I hope the half-dozen players out injured will be fit for the next game, which happens to be England, and they will come into consideration. Of course the England game is important, but at this stage of my job I am certainly not going to be blinded to the bigger picture by one big match."
There will be no Ryan Giggs at Swansea's New Stadium, the Manchester United man is out with a chest infection, while Craig Bellamy (ankle), Ben Thatcher (ankle) and Simon Davies (shin) are all out - Craig Davis is called up from the under-21s.
Swansea-born Richard Duffy - who will make his debut tonight - could be the first of many new faces in the months ahead.
"We have a dozen matches before the European Championship qualifiers start in September, 2006," Toshack said. "What we have to do over the next 12 months is prepare a squad of players who can attack the European Championship qualifiers.
"And if they miss out on that they will still be around to attack the next World Cup. In these next dozen games we must push on and bring younger players into the squad.
"Whether we are playing Slovenia, England, Poland, Northern Ireland or Azerbaijan, we will use these games to look at different ways of playing.
Wales will play in a new "third" kit at Swansea, all black with white and red stripes in honour of the late John Charles, who died last year. The colours are the black, white and red of Juventus, Leeds and Wales respectively.
* The Northern Ireland manager, Lawrie Sanchez, has questioned the attitude of the Sunderland full-back George McCartney, who has no wish to play for Northern Ireland while Sanchez is in charge. "Everyone knows the situation regarding George and his commitment, especially since I became manager." Sanchez's side play in Malta tonight.Reuse content