Should the Dodgers be concerned about Kenley Jansen’s velocity?

The line of questioning perturbed Kenley Jansen. He had reason to be upset. His Dodgers were winless after two games in 2018. His teammates on offense had yet to record an extra-base hit, let alone score a run. In a 1-0 defeat to San Francisco on Friday, Jansen wore the loss after giving up a home run in the ninth inning to Giants second baseman Joe Panik.

Jansen surrendered the blast on an 89.6 mph cutter, a pitch which registered well below the velocity he had displayed en route to a pair of All-Star teams and a five-year, $80-million contract. During the past year, Jansen has emerged as an outspoken leader of his team. He will pontificate on the Dodgers’ internal dynamics, the labor issues roiling the sport and the scourge of pace-of-play initiatives.

But he did not want to talk about his velocity.

“Who cares?” Jansen said.

He repeated himself on several occasions. He sounded unhappy.

The first 18 innings of the 2018 season did not treat the Dodgers well. The offense looked pitiable. Logan Forsythe made three errors at third base on Friday. The Dodgers wasted a sparkling outing from Alex Wood and a serviceable one from Clayton Kershaw the day before. There has not been much for fans at Dodger Stadium to applaud.

The meaningfulness of these two games is minimal. But there have been some troubling trends that will deserve study during the course of the season: the velocity of Kershaw’s fastball and Jansen’s cutter. Both looked diminished in their debuts.

This did not catch the Dodgers off guard. Near the end of spring training, team officials noted a dip in velocity for several of their pitchers, which could be a product of the group playing into November last season. It would be up to the pitchers to adapt.

During six innings on Thursday, Kershaw’s fastball velocity sat at 92.0 mph, according to Brooks Baseball. It maxed out at 93.1 mph. A year earlier on opening day against San Diego, Kershaw threw fastballs that averaged 93.0 mph and touched 94.8 mph.

Kershaw is not unaware of this trend. His fastball velocity decreased slightly as he returned from the disabled list last summer. He might make more adjustments as the season progresses.

“I mean, I’d always like to throw harder,” Kershaw said. “Yeah, sure, I’ll throw 100 if you let me.”

The aging curve does not take requests. But Kershaw wields two offspeed pitches, and can at least deviate from his fastball. On Thursday he threw more sliders than heaters.

Jansen has improved his command of the slider, but he relies upon his cutter. Unlike Yankees legend Mariano Rivera, Jansen favors pumping cutters in the upper half of the strike zone. He allows more flyballs than grounders. A ball on the ground cannot leave the yard. A ball in the air can.

That was what happened on Friday. Catcher Yasmani Grandal set up high and inside. The cutter bent over the heart of the plate. Panik sent it into the first row of the bleachers.

“I tried to go in, and it didn’t go too far in,” Jansen said. “It just stayed over the plate, and he got a shot.”

The cutter registered below 90 mph. Jansen remained there on the aggregate for his appearance. He finished with an average velocity of 89.6 mph. He did not throw a pitch harder than 90.4 mph. During his first outing in 2017, Jansen sat at 92.3 mph and topped out at 94.2 mph.

Roberts acknowledged that the decrease in velocity caught his attention. The dip was hard to miss.

Roberts indicated that Jansen’s fastball hit 94 mph in his second outing of the spring. But Jansen pitched sparingly in the Cactus League, as the team opted to keep him fresh after his heavy workload in 2017. Roberts suggested Jansen was dealing with mechanical issues.

“For Kenley, as I’ve learned him over the years, when the velocity’s down, there’s kind of a mechanical thing that’s not right, that’s not synced up,” Roberts said. “He’s a big-body guy. I do think that when you’re talking 4 miles an hour, 3miles an hour below .... It’s not a health thing. He feels great. Feels strong.

“It’s not a usage thing. So I think it is a mechanics thing, that I think he and [pitching coach Rick Honeycutt] are going to work through. And that ball to Panik was inner-third, belt-high and it was 89. It was kind of a cement mixer right there. In his nitro zone. Very uncharacteristic for Kenley.”

Jansen rejected that assessment.

“No, man, it’s not mechanics,” Jansen said. “He just got me.”

A reporter mentioned the 89-mph velocity. Jansen remarked, “Who cares?” four times.

Fans care, Jansen was informed. Jansen disagreed with that as well. He suggested the media is more concerned about his velocity than the fanbase.

“It’s one game,” Jansen said. “You guys care about it.”

Jansen shook his head. The interview ended. His pace was measured as he departed the clubhouse.

andy.mccullough@latimes.com

Twitter: @McCulloughTimes