Keown wrote in the Daily Mail: "Gary Cahill has made great strides in the last few seasons which means losing John Terry is no longer such a big deal.
"Cahill's got very good technique and quick feet for a centre half and he's stepped up at Chelsea.
"As you mature as a defender the key is making fewer and fewer mistakes and he's doing that.
"He also scores goals from set pieces - which is key for England. In fact, Cahill is similar in many ways to Terry."