The left-hander has been on the disabled list since April 28 because of inflammation in his throwing shoulder.
He threw a bullpen session Tuesday and a four-inning simulated game Friday.
With Ryu returning to the rotation, veteran left-hander Paul Maholm will move to the bullpen.
In seven starts, Maholm is 1-7 with a 5.50 earned-run average.
Ryu has also made seven starts and is 3-2 with a 3.00 ERA.