Steffen played an hour of a training ground reserve game last week after being out since January with cruciate ligament damage and came through without any problems.
He will be joined in a young side by new boys Rohan Ricketts and Diego Bortolozzo, while Chris Perry will bolster the defence.
Coach Colin Calderwood is hoping that his side can match the first team in securing full points against the Saints.
"Twice we played them last season and they beat us both times, so it would be nice to get something from them this time," said Colin.
"We'll go with a fairly young side and hopefully we can build on our pre-season. It will be a good test for them. It's an opportunity for the lads to stake their claim."
Meanwhile, our reserve away fixture against Nottingham Forest, scheduled for Tuesday 24 September, will now be played 24 hours earlier on Monday 23 September at the City Ground.
Steffen Freund makes his first competitive return to action as our reserve side play their opening home match of the season against Southampton at Stevenage tonight, kick-off 7pm.