Ryu, 30, has been limited to just one regular season start the past two years with shoulder and elbow problems, after winning 14 games in both the 2013 and 2014 seasons. In spring training, Ryu has posted a 2.57 ERA across four appearances, yielding four earned runs in 14 innings.

Against the Chicago White Sox on Monday, Ryu went five innings -- his longest outing of spring training -- and allowed three runs on five hits in a 5-2 defeat. He struck out four and walked none.

A torn labrum in his left shoulder cost him the entire 2015 season. He returned to make one start in July last year and then was shut down for the rest of the season with elbow pains.

Ryu has gradually increased his workload this spring and threw a preseason-high 77 pitches against the White Sox.

Ryu worked his way into a rotation fronted by three-time Cy Young Award winner Clayton Kershaw, Kenta Maeda and Rich Hill.

Roberts said Brandon McCarthy and Alex Wood will fight for the final spot in the five-man rotation, with another candidate, Scott Kazmir, going on the disabled list with a left hip injury.

Ryu looked shaky in the first inning Monday, as he gave up a solo shot to Melky Cabrera and was unable to find the strike zone against other hitters.

Ryu retired the side in order in the second inning and worked around a leadoff bunt single by Leury Garcia in the third.

With the Dodgers up 2-1 in the fourth, Ryu gave up a two-out single to Matt Davidson, and Yolmer Sanchez followed that up with a two-run home run to left-center field.

The left-hander came back out for the fifth inning and stranded a two-out single in his final frame.

Ryu's record fell to 0-2, but he has generally looked healthy in all spring outings.

Ryu joined the Dodgers on a six-year, $36 million deal signed before the 2013 season, becoming the first South Korean pitcher to jump from the Korea Baseball Organization to the majors via posting. (Yonhap)