Kenny Jackett has revealed fears Ross McCrorie would be sent off prompted him to sub the Scotland U21 captain in a 1-1 draw with Oxford.
McCrorie was named man of the match during the game but the Rangers loanee was hooked with his side a goal up.
Oxford found an equaliser in the last minute and Jackett was criticised for his decision with Portsmouth in poor form and sitting 15th in League One.
But the Pompey boss has defended the move and insists it was down to red card fears for McCrorie.
The 21-year-old was sent off on his Portsmouth debut and has struggled to get a regular role in the team since.
He has got back in while playing right back and the versatile youngster was the best player on the pitch on Saturday.
But he was booked for a first half tackle on Josh Ruffels and Jackett told the Portsmouth News: "It was just to make sure Ross didn’t get sent off.
"He was on a booking and there are sometimes situations he puts himself into. I didn’t want to go down to 10 men.
"Ross was on a yellow and then made a foul mid-way through the second half, where it did look like one more and that could be it.
"He brought a lot to our game and is learning all the time. In terms of bookings, he has to be careful and learn from that – and he can and will keep improving.
"He has found his feet now, there have been quite a number of changes in the summer and he is one of them. I am pleased with him.
"We persevered with him and there is a player there, definitely."
