“Firstly, I think Jack Buckland is a top goalkeeper. Secondly, I’ve got a very, very good relationship with Jack.
“I’ve known Jack a long time. He was a young kid coming through at Birmingham when I went down to play for Birmingham in the Premier League.
“Thirdly, I’ve got to know it’s hurting Jack and I’ve got to be mindful of that as well. Because I care for him.”
Ferguson felt “I just had to make a decision”, with Butland one of six changes from the side that slumped to a fifth consecutive home defeat for the first time in the club’s history.
“It was a tough decision when I spoke to him,” he said. “I could see it was hurting. You go with decisions.
“It’s not one that I decided on Saturday night or Sunday. I thought long and hard about it.
“When I spoke to him, it was a tough 10-15 minutes conversation. But, listen, Jack’s still got a huge part to play here.”
Rangers, sitting second and possibly needing a win to delay city rivals Celtic’s title party, travel to face Aberdeen on Sunday before next Thursday’s second leg in Spain.
The 29-year-old Kelly could be asked to continue in goal after making a couple of other fine stops on top of diverting Alex Berenguer’s late spot kick over the crossbar as Rangers held on to draw a game in which they had centre-half Robin Propper sent off after only 13 minutes.
“In terms of Liam coming in, I thought he’d done well tonight,” Ferguson added.
