JUPITER, Fla. -- Victor Robles has yet to play a full season, but his ceiling is off the charts. When asked on Saturday to compare Robles to any other Major Leaguer, Nationals manager Dave Martinez sat and thought about it for a few seconds, then offered the name of the Giants' Andrew McCutchen.
"It's still early to say, all I know is that he's a really good athlete and he's only going to get better," Martinez said of the Nats' top prospect and the No. 6 prospect in baseball, according to MLB Pipeline. "But he's young and he's really honing in on the baseball skills and the little things."
Robles, who doubled and walked in the Grapefruit League opener on Friday, went 1-for-3 in Saturday's 3-2 loss to the Marlins at Roger Dean Chevrolet Stadium.
"I feel great to be compared to a great ballplayer like Andrew McCutchen. How can you not feel great about that?" Robles said. "To be compared to him is amazing."
But first things first, making the team would be a good start. Robles said he isn't feeling the pressure to create a big splash right away, but more to continue to improve.
"I have the same mindset that I've always had," Robles said. "Just come up here and do my work, play baseball. I obviously want to make the team, but that's not what I'm worried about. I can't control that."
Doolittle slider coming along
Hard-throwing closer Sean Doolittle is working on his offspeed pitches this spring. That can't be good news for opposing hitters. The National League as a whole is still trying to catch up to his heater, and now the left-handed fireballer is attempting to be even more nasty.
Martinez said he has kept an eye on the slider that Doolittle is working on.
:: Spring Training coverage presented by Camping World ::
"It's actually pretty good," Martinez said. "He says he's going to try to develop it as he gets in the games and throw it a little bit more to get the feel for it.
"I told him to work on what you need to work on, but remember what got you where you're at and why you're good. But I like the fact that he's trying different things."
Many pitchers don't survive for very long on one pitch, but Doolittle has made a successful career with it.
"He's mastered it," Martinez said. "I think with him is he knows how to get hitters out. He commands his fastball really well."
Doolittle set a career high with 24 saves last season, including 21 for the Nationals. He posted a 2.40 ERA for the club over 30 innings.
Jackson struggles in debut
Edwin Jackson pitched two innings out of the Nationals' bullpen on Saturday, allowing three hits -- one of those a solo home run by Marlins designated hitter J.T. Realmuto. He struck out one in his first Grapefruit League outing, a 34-pitch effort (20 strikes).
In what capacity Jackson could be used is still to be determined. He went 5-6 with a 5.07 ERA in 13 starts for the Nationals last season.
Washington re-signed Jackson to a Minor League contract in January.
Big bro's debut
Bryce Harper's big brother, Bryan Harper, worked the eighth inning. The 28-year-old non-roster invitee gave up the go-ahead run on two hits and a hit by pitch. He escaped more damage with an inning-ending double play.
Harper has spent six seasons in the Minor Leagues, reaching as high as Triple-A Syracuse.
Up next: The Nationals return home to face the Braves at 1:05 p.m. ET on Sunday (MLB.TV). Reigning NL Cy Young Award winner Max Scherzer gets the start for Washington, opposed by Atlanta lefty Scott Kazmir.