"Jonny did really well last week when he came on against Bath and was putting a bit of pressure on Ryan," said Ruddock.
"Ryan has stepped up to the mark, but he has unfortunately hurt his rib cartilage so he is probably going to be out for a couple of weeks.
"Jonny looked very assured. One piece of skill comes to mind when he kicked just down the blindside and, if it had rolled out to touch five minutes from time and just away from their line, it could have been a significant moment.
"As it turned out they managed to clear, but Jonny is a good little player who shows a lot of composure and skill."
After the game, Ruddock reported fresh injury worries in the front row as both Callum Black and Tevita Taumoepeau suffered leg problems.
"Tevita and Callum both pulled calf muscles - it looks like they are both going to be missing next week," he added.
"But we have still got Jack Gilding and Adam Black and Olivier Sourgens both did fantastically well when they came on and got a scrum against the head late on."