Don Mattingly trying to arrange a little relief for Dodgers relievers

The Dodgers bullpen finally hummed into motion Friday night when Chin-hui Tsao hopped up, tucked in his uniform jersey and began his warmup routine.

It was later than expected, the sixth inning of a 3-2 Dodgers win against the Milwaukee Brewers. Right-hander Mike Bolsinger had pitched admirably, allowing two earned runs across six innings, an unusually long outing for the right-hander.

The start kept the game close enough for Tsao to earn the win in his first major league appearance in 2007. Bolsinger’s wasn’t quite a deep outing, but the Dodgers will take it — even if they wonder how many more like it they will get from the back end of the rotation.

The bullpen’s workload has become an issue. The concern is not about total innings pitched as much as appearances on consecutive nights. With No. 4 starter Bolsinger and the final spot in the rotation, the bullpen is usually kept busy.

“You’ve just got to hold your breath a few games in there that you know you’ve only got a couple of guys available or you know your bullpen’s really short,” Dodgers Manager Don Mattingly said.

Mattingly plans to separate the starts of Clayton Kershaw and Zack Greinke after the All-Star break. Both often work deep into games, which gives the bullpen an easy night. They typically pitched on consecutive days during the season’s first half.

The Dodgers are trying to avoid a situation like last season, when bullpen issues were part of the team’s postseason demise. Closer Kenley Jansen has said this year is a “completely different group.” But the workload has begun its erosion.

On Wednesday, the Dodgers demoted right-handed reliever Yimi Garcia, who had blown past opposing batters to start the year but, in his final four appearances, had given up six runs in four innings and blown a save.

The Dodgers blamed overuse and sent him to the minor leagues to recuperate.

The issue wasn’t just Garcia. In some games, Mattingly, wary of the bullpen’s workload, has had his hands tied when considering a pitching change.

“There’s probably been some games where I’ve left guys in, and fans are like, ‘Get him out of there,’” Mattingly said.

But there were no other options, he said.

“There’s times you’ve just got to swallow, you know?” Mattingly said.

Jansen said innings now can weigh on a reliever later in the season, like a car with high mileage.

“Your workload’s going to carry even more for the playoff push in September,” Jansen said. “It’s going to be a difficult time for the bullpen, and when you get those days off, you enjoy it the best you can.”

The Dodgers’ bullpen has actually thrown 16 innings fewer than the National League average. But the team has used 13 different pitchers as it has scrambled to keep arms fresh.

The problem has been back-to-back short starts. Friday was just the second time Bolsinger had gone more than 51/3innings since May. His average start is five innings. The average start for Carlos Frias, who went on the disabled list July 1 with lower back tightness, is 5 2/3 innings.

Each man has thrown 100 pitches or more just once.

In Frias’ place, the Dodgers announced right-hander Brandon Beachy will make his first start in more than two years after recovering from a second reconstructive elbow surgery. Beachy threw 92 pitches in his most recent rehabilitation start with triple-A Oklahoma City. Is he prepared to throw every fifth day?

“I believe so,” he said. “There’s only one way to find out, right?”

Bolsinger threw just 83 pitches Friday, but his spot in the order came up in the sixth inning. At that point, the Dodgers didn’t have a hit. Mattingly opted for the pinch-hitter.

The Dodgers took the lead in the seventh inning on a high, looping Joc Pederson double that hit off the wall and scored two runs. The lead was slim, just one run.

But after consecutive Kershaw and Greinke starts, the bullpen had thrown just one inning in two games.

With plenty of rest, they didn’t give up another run.

zach.helfand@latimes.com