The LA Dodgers had high hopes for rookie Roki Sasaki, who was posted in the offseason and brought in by the franchise amid intense competition from other teams. Unlike most international signings, the Dodgers inserted Sasaki in the rotation, but he hasn't had the kind of season he was used to in Japan.
Before hitting the injured list after a shoulder impingement injury on May 9 in a start against the Arizona Diamondbacks, Sasaki had gone 1-1 in eight games started, which saw him throw 39.1 innings for a 4.72 ERA.
The low returns have Dodgers manager worrying, as reported by Matthew Moreno, who posted:

"Dave Roberts and Mark Prior both have said Roki Sasaki was pain-free. But this was Roberts today: "I don't know if he's feeling something, or he just doesn't have the confidence to kind of trust that he's in a good spot.""
Dodgers manager provides latest update on Roki Sasaki
The LA Dodgers have seen several of their starters go down with injuries. Roki Sasaki is among them, and there's a latest update in store ahead of the team's three-game series against the San Francisco Giants.
Dodgers pitching coach Mark Prior said that the franchise is taking it easy with Sasaki.
“Not a whole lot to report on Roki. I think right now we’ve got to get him in a position where he feels confident in his ability to throw the baseball," Prior said via SI.
“There’s not a lot to report. He’s been throwing, still just light catch and not a lot of work other than light catch right now. … He is pain-free, but hasn’t gotten to the point where he can put enough intensity to push forward in his progression. It’s just a light catch, just exercising in his throw and not necessarily pushing the throw.”
The Dodgers are hoping for Sasaki to take back his spot in the rotation, which includes Clayton Kershaw, Dustin May and Yoshinobu Yamamoto. Apart from Sasaki, Tyler Glasnow and Blake Snell are also injured.