Dave Roberts discusses whether Dodgers will option Roki Sasaki to minors

Although he was a highly touted international prospect, Los Angeles Dodgers starting pitcher Roki Sasaki has stumbled at the start of his major league career.

The 23-year-old entered the season as MLB's No. 1 prospect after he posted a stellar 2.10 ERA in four seasons with the Chiba Lotte Marines of Nippon Professional Baseball, Japan's highest baseball level. 

That success hasn't translated to the majors. Through 34 1/3 innings, Sasaki has posted a subpar 4.72 ERA with 24 strikeouts and 22 walks. In his latest start against the Arizona Diamondbacks on May 9, he allowed a season-high five runs in four innings.

Despite the early struggles, Dodgers manager Dave Roberts doesn't think demoting the young pitcher would be beneficial.

"I don't think a Minor League stint is in any of our minds right now," Roberts said Tuesday, via Sonja Chen of MLB.com. "But I do think that this learning up here is very, very valuable." 

One thing the Dodgers have learned about Sasaki is that the velocity on his fastball is dropping. 

According to Statcast, Sasaki's fastball has averaged 96 mph this season, in the 80th percentile among qualified Major Leaguers. However, Chen noted that he was reaching triple digits in NPB. 

Roberts explained that Sasaki must improve his command to compensate for the slower speeds. 

"When you're throwing mid-90s, 94 [mph] then you got to really command the baseball. So, that's what we're working on as a group," Roberts said. "Roki understands that. And this is still his first season here, so there has to be some grace, as he's kind of learning this league and kind of getting his footing."

While Roberts is preaching patience for Sasaki, he knows he must show signs of progress soon. 

The Dodgers' starting pitching problems could prevent them from repeating as World Series champions. Through its first 41 games, L.A. ranked 26th in baseball in quality starts (10). To solve these problems, the Dodgers need more from Sasaki.