Los Angeles Dodgers pitcher Roki Sasaki had a rough outing against the Arizona Diamondbacks on Friday, drawing criticism from manager Dave Roberts.

Sasaki completed only four innings of work, allowing five earned runs on five hits and two walks. He also did not record a strikeout in the game.

His performance felt like a step backwards, with Roberts acknowledging that the Japanese pitcher did not have his best stuff.

“I just felt tonight he was laboring from the outset,” Roberts told reporters after Friday’s game to reporters.

“You could tell by facing 20 hitters and not one strikeout. Guys were taking really good swings. He didn’t have (anything) tonight to put guys away.

“I just didn’t feel that he was particularly sharp tonight and commanding the fastball, the split, all that stuff.”

It is notable that Sasaki is pitching in his first game with only five days of rest, which is a regular schedule for American players; however, in Japan, pitchers take the mound only once a week.

Due to injuries to Tyler Glasnow and Blake Snell, both Sasaki and fellow Japanese pitcher Yoshinobu Yamamoto had to adjust their schedule to pitch on five days’ rest.

In his previous start, Sasaki secured his first major league win, pitching five innings and allowing three runs, with two walks and four strikeouts against the Atlanta Braves.

At just 23 years old, the Dodgers have thrown Sasaki into the deep end, testing him against MLB hitting without allowing him to gain experience in minor league games, and his learning-on-the-fly approach has yielded mixed results so far.

One of the bigger concerns about Sasaki is his fastball velocity, which was near 100 mph during his time in Japan and his debut; however, he has noticeably reduced the speed of the pitch.

Dodgers pitching coach Mark Prior said Sasaki was trying to throw the heater less forcefully in order to gain better command of the pitch.

The pitch is now around 94 mph, making it much more hittable. Sasaki seems to be trying to adjust from game to game to gain confidence and understand the ideal pitch mix that works best for him.

The issue for Sasaki is that if his fastball is not going to be a weapon, then his only other legitimate strikeout pitch is his splitter. If neither is firing, then there will be more games like the one against Arizona.

Given the Dodgers; injury issues, he will have to learn and adjust as he goes.