GLENDALE, Ariz. -- Dodgers manager Dave Roberts confirmed that Mookie Betts will be his primary leadoff hitter this season. Betts has hit leadoff in 562 of his 780 MLB starts.

“Mookie has talked to me about wanting to be at the top, that's where he feels comfortable,” said Roberts. “And that's where we're at right now. But I can't say that -- as we look at the thought of if it makes sense for the lineup -- against a particular right-hander, [we won't] flip a left hand at the top to have Mookie second. But right now, I see Mookie at the top and that's what we're going with.”

While Betts was acquired to provide right-handed balance to an already-loaded lineup, Roberts didn’t sound like he will abandon his tendency to move players in, off and around the diamond.

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“Cody [Bellinger] at center and first, A.J. [Pollock] in left and center, Mookie is going to be in right field, [Max] Muncy first and second base and potentially at third, [Matt] Beaty at first, third and left,” he said. “There's just a lot of different ways and obviously CT [Chris Taylor] and Kiké [Hernandez], they can essentially play anywhere on the diamond. I'm going to do everything I can to keep everyone as relevant as possible.”

Jansen working on slider
Closer Kenley Jansen, who threw live batting practice on Thursday, followed up on Friday with a bullpen session to work on his slider with Rick Honeycutt, Orel Hershiser and Joel Peralta.

“In Spring Training, why would you work on your cutter, on your two-seam, and forget about your slider?” Jansen said. “I want to make sure all three pitches are A-plus. I tried three different grips today, the last grip I kind of liked it, it was hard-down.”

Jansen said he was very pleased with the action of his cutter and two-seamer facing hitters on Thursday.

“I loved my live BP yesterday,” he said. “I got a lot of movement, the hitters will tell you. J.T [Justin Turner], Cody and Max -- they all say the cutter is moving. I threw a few sliders, but they can get better.

“I spent a lot of time this offseason working on my cutter, a little on the two-seamer and I feel like I have the feel of them. Why not spend a couple weeks getting better on the slider? Just imagine if you can have the slider as a weapon. Now you talk about three pitches as weapons and it can ease things out there.”

Nelson throws clean bullpen
Roberts said Jimmy Nelson (groin, lower back) came out of his Friday bullpen session healthy.

Pederson's sore hip
Joc Pederson had a light day on Friday to receive treatment for a sore right hip, which he said was minor.

No Betts in Cactus League opener
The Dodgers open the Cactus League season on Saturday (vs. San Francisco at 12:05 p.m. PT), weather permitting. There’s a 100 percent chance of rain in the forecast for Scottsdale, where Tony Gonsolin will start for the Dodgers.

National League MVP Bellinger and fellow All-Star Muncy are expected to be in the starting lineup, but Betts' Dodgers debut is more likely to occur Sunday at home against the Cubs.