Dave Roberts, Dodgers open spring training with plenty of questions to answer

Reporting from phoenix —  The Dodgers’ 2019 season unofficially launched at 11 a.m. local time Tuesday, hours after pitchers and catchers reported for spring training at Camelback Ranch. Four pitchers lined up on mounds next to each other, four catchers on the receiving end, waiting.

The bullpen sessions continued until Clayton Kershaw took a mound alone just before 11:30. A couple of dozen people watched as he unloaded his arsenal to Russell Martin, a familiar batterymate.

Kershaw — and whether he will pitch any differently — is one of the spring’s intriguing story lines surrounding the Dodgers, but he’s far from the only one.

Corey Seager was among the position players at the complex as he continues rehabbing following elbow-reconstructive and hip surgeries. Dodgers manager Dave Roberts said Seager isn’t running “100%,” hasn’t thrown across the diamond, and the club isn’t sure when he’ll be cleared to play in Cactus League games. But Roberts was optimistic about the shortstop’s chances of being ready for the start of the season.

“We’re tracking for him to be ready for opening day,” Roberts said.

Seager’s first games will be on the back fields, among minor leaguers, to accumulate at-bats before playing in spring training games. Every player is different, but Roberts estimated it would take 50 to 60 at-bats for Seager, 24, to be ready for the regular season.

“That’s dependent on how Corey feels,” Roberts said. “And as far as fielding, that’s something else. Because to be able to just stand in the infield, to have your legs, we’re going to have to create some situations to see how many defensive innings he can log because, arguably, that’s going to be harder than the at-bats.”

Kenley Jansen was on a similarly careful plan last year after two seasons of heavy workloads. This spring, following his worst season as a closer, the 31-year-old Jansen will take a more aggressive approach after undergoing a heart procedure and losing 25 pounds during the offseason. He will partner with Joe Kelly and Pedro Baez at the back end of the Dodgers’ bullpen, giving the club three right-handers to hopefully stabilize the relief corps.

Despite trading pieces from both areas, the Dodgers still boast surpluses in the outfield and starting rotation. Roberts said A.J. Pollock, signed last month, would be the everyday center fielder and Cody Bellinger would get the bulk of his reps in right field this spring while spending some time at first base and center field. That leaves Joc Pederson, Alex Verdugo, and Andrew Toles vying for at-bats and time in left field.

Injuries notwithstanding, Kershaw, Walker Buehler, Hyun-Jin Ryu, and Rich Hill are expected to populate the top four spots in the Dodgers’ rotation. The fifth slot will come down to Kenta Maeda and Ross Stripling, with Julio Urias on the fringe, after the Dodgers shipped Alex Wood to the Cincinnati Reds. Dodgers officials said during the offseason that they view Maeda as a starter. They weren’t as explicit about Stripling, who made the All-Star team as a starter last season after beginning the season as a reliever. At the end, he didn’t make the Dodgers’ playoff roster in any capacity.

“Ross is a guy that’s very versatile,” Roberts said. “I know his desire. We know his desire to be a starter. So right now there’s going to be seven, eight, nine guys that we’re essentially going to build up for the next month and see where it takes us, because a lot can happen between now and Opening Day.”

Behind the plate, the Dodgers will have Austin Barnes and Martin, two catchers looking to rebound from disappointing offensive seasons. How innings are divided between them remains unclear. That too will be decided over the next six weeks as the two-time defending National League champions undertake another quest to break through in October.

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jorge.castillo@latimes.com

Twitter: @jorgecastillo