© 2014 MLB Advanced Media, L.P. All rights reserved.

4/24/2014 10:00 P.M. ET

Mattingly challenged by outfield surplus

LOS ANGELES -- Manager Don Mattingly said on Thursday that the Dodgers' excess of healthy outfielders has made his lineup decisions more stressful.

Mattingly said "there will come a day" when there's "just a clearer picture" of who will start and who won't. He said that doesn't mean he will stick with only three starters every game and relegate one to a bench role.

Mattingly has tried to rotate Yasiel Puig, Matt Kemp, Andre Ethier and Carl Crawford into the three starting spots, often citing statistical-matchup history or righty/lefty preference. Further complicating Mattingly's decisions, Scott Van Slyke has become invaluable against left-handed pitchers by hitting .444 against them.

None of the core four is on fire offensively and Mattingly said he didn't know if that was the result of irregular playing time. Puig is batting .269, Kemp .218, Crawford .217 and Ethier .206. Kemp has the highest slugging percentage at .473 and Puig the highest on-base percentage at .355.

Mattingly left Kemp out of Thursday night's lineup, even though he's 6-for-15 lifetime against Phillies right-handed starter Kyle Kendrick and had two doubles Wednesday night.

"I think Matt is disappointed," said Mattingly. "He swung the bat good last night."

Calling the lineup dilemma "a little bit of a problem," Mattingly said "there will come a day" where it will "work itself out," but he stopped short of suggesting how that might happen.

"It's not so much that you're hurting feelings," he said. "You want everybody in the mix. But you've got four guys with quality careers and you can't just throw those aside. I assume every time a name is not in the lineup, they're not happy about it."

Including Thursday night's game, Kemp had started 14 games, Puig 16, Ethier 16, Crawford 13 and Van Slyke six in the outfield.

Kemp, Ethier, Crawford and Puig are signed to long-term contracts through at least 2017. Management has been reluctant to trade any of them because Kemp and Crawford have significant histories of injury.

Dodgers hope to ease Jansen's workload

LOS ANGELES -- Dodgers closer Kenley Jansen has appeared in 15 of the team's 22 games heading into Thursday night's series finale with Philadelphia.

That puts Jansen on pace to appear in 110 games, which would break former Dodgers pitcher Mike Marshall's Major League record of 106 appearances set in 1974, when Marshall pitched a staggering 208 1/3 innings out of the bullpen, went 15-12 and earned 21 saves in 33 opportunities.

The Dodgers are extremely hopeful that Jansen threatens none of those stats.

"We're paying attention," said manager Don Mattingly. "There are a lot of factors. Our starters have been 12th in innings pitched. Our bullpen has pitched 80 innings. We've asked a lot of innings out there. Now we're playing 29 of 30 [days].

"I know that pace can't keep up and I don't think it will. You'll see it get better."

Jansen, who pitched four of the previous five days, said Thursday that his arm feels fine.

"It usually does in April and August," he said. "I'm fine."

Mattingly remains mum on Kershaw's return date

LOS ANGELES -- Clayton Kershaw will make a Minor League rehab start for Class A Advanced Rancho Cucamonga on Friday night.

Manager Don Mattingly would not say how soon Kershaw might return to the Dodgers' rotation, but neither would Mattingly confirm who would start for him next week in Minneapolis, where the Dodgers open a three-city trip.

Kershaw has been on the disabled list since suffering a strained teres major muscle on the left side of his back in his Opening Night win in Australia. It is Kershaw's first time on the disabled list.

On Wednesday, Mattingly said Kershaw would need at least a second rehab start before being activated. Kershaw will probably lobby to return immediately if Friday night goes well. He is expected to make 55-65 pitches and his next day to pitch would be Wednesday. The Dodgers have a travel day on Monday.

Kershaw's spot in the rotation has been filled by Paul Maholm, who is scheduled to pitch Saturday and again next Friday.

Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.