With financial uncertainty still swirling around Tynecastle, the midfielder - who has not played since February - was back in action on Tuesday night.
He played the opening 45 minutes of the 5-1 friendly defeat to Dinamo Bucharest in Manchester; Jamie Hamill hitting Hearts' only goal of the game from the penalty spot.
Robinson was returning after surgery to repair torn knee cartilage, and Locke said: "That was his first game for quite a few months and I thought that he did well considering that. He has still got a bit to find in terms of his fitness.
"He has been out for a long time and it takes you a while to get back to where you were.
"But he's now got 45 minutes under his belt against a very good side and he has got to take the positives from that.
"Hopefully we can give him another hour or so on Saturday so that we can build for the start of the season."
Hearts' next pre-season action will be against Dunfermline at East End Park on Saturday 13 July.