BOSTON -- While Joe Kelly’s revival has provided optimism that the Dodgers have the right-handed reliever needed for high-leverage situations, the continued absence of Scott Alexander underscores the need to add a left-handed reliever before the July 31 Trade Deadline.

Alexander went on the injured list June 11 with left forearm inflammation and was expected back long ago, but manager Dave Roberts said the left-hander remains at the club’s Arizona training complex indefinitely.

“Still not healthy,” Roberts said. “It’s dragging on longer than we thought. There’s no new diagnosis, it’s just taking longer than we expected.”

With Alexander out, Tony Cingrani lost to season-ending shoulder surgery and Caleb Ferguson back in the Minor Leagues, Roberts has leaned on Julio Urías to be the lefty getting the bulk of the work. The only other left-hander currently in the bullpen is Zac Rosscup, who in the past year has been with Colorado, the Dodgers, Seattle, Toronto and the Dodgers again.

Urias originally was put in the bullpen to save innings on his arm, which would allow him to return to the starting rotation later in the year, although he might be needed more where he is. Rich Hill, out until September with a strained flexor tendon, might also become a left-handed relief option.

While the trade market might be too frothy for the Dodgers to be the club that overpays for lefty relievers Will Smith, Brad Hand or Felipe Vázquez, they figure to be creatively searching for a solution like two summers back, when they brought in Cingrani and Tony Watson.

As for Kelly, he’s left behind a dreadful April. Since May 8, he’s 2-1 with a 1.56 ERA and 24 strikeouts in 17 1/3 innings. That’s what the Dodgers were counting on when they signed him to a three-year, $25 million free-agent contract coming off a World Series hero performance for Boston against the Dodgers.

“Joe’s in a really good place, throwing the baseball really well,” said Roberts, who said he plans to continue using Kelly for single innings. That’s a shift from the multiple innings for which the Dodgers originally believed he’d be utilized.

Ferguson got a start for Triple-A Oklahoma City in Saturday’s doubleheader, the result of a scheduling adjustment because of approaching bad weather and not a change of roles, Roberts said.