Speaking to BBC Radio Five Live, Southgate said: "Our plan today was half an hour and he'll start on Friday. He had the audacity to ask to come on and to score the penalty which was never going to happen! The great thing is we've got through the last few days with no new problems.
"That's really important. We needed to get through these first matches to get a clearer picture. The guys rehabbing have done well. [Bosnia] were an opponent that were dogged, determined.
"Physically, it was a good workout but in the end, a good performance. The scoreline reflected the performance. We had a lot of fresh players to bring in. Once you break that resistance then it starts to come."