Exam on Matt Kemp’s left shoulder confirms irritation of AC joint

PHOENIX — Matt Kemp underwent an MRI exam on his left shoulder Tuesday that confirmed the medical staff’s original diagnosis of irritation in his AC joint, according to Dodgers Manager Don Mattingly.

Kemp received an injection of platelet-rich plasma and is expected to be ready to be activated on July 21, the day he is eligible to return from the disabled list.

Kemp underwent the exam in Los Angeles, where he was seen by team physician Neal ElAttrache. The medical staff remains convinced that Kemp’s latest injury is unrelated to the labrum surgery he underwent in the off-season.

Kemp injured his shoulder swinging and missing at a pitch on Friday. He was put on the DL three days later.

He had a similar discomfort in his AC joint in April. He received a cortisone injection and played two days later.

Kemp’s issues with his AC joint predated his head-on collision with the outfield wall in Colorado last year that led to his operation.

The Dodgers aren’t concerned that Kemp’s AC joint will present long-term problems. Even if surgery is required, the procedure would be minor. Javy Guerra underwent surgery last winter to clean up his AC joint and was ready to pitch in spring training.

Lilly to the bullpen?

Ted Lilly asked Mattingly to consider using him out of the bullpen, as the 37-year-old left-hander acknowledged he isn’t recovering well from his starts.

Lilly is on the DL for the third time this season because of a strained neck. He pitched in a minor league game Saturday and said his neck bothered him the next day.

“I’ve had a hard time staying healthy,” Lilly said.

Mattingly said Lilly could pitch in a simulated game as early as Wednesday.

“I want to be open-minded to see what it looks like,” Mattingly said.

As a starter, Lilly is 0-2 with a 5.09 earned-run average in five games.

“Obviously, the idea is to try to figure out what’s best for us as a club,” Lilly said. “I want to pitch well, whenever it is or whatever the role.”

Lilly has spent 67 games on the DL. During his downtime, he has thought about retirement. Lilly is in the final year of a three-year, $33-million contract.

“I want to play if I can be effective,” Lilly said. “I’d like to play for a long time, but I certainly don’t want to be on the DL day after day.”

Short hops

Yasiel Puig remains in second place behind the Atlanta Braves’ Freddie Freeman in online voting for the final spot on the National League All-Star team. Kobe Bryant offered his support to Puig’s candidacy, posting, “#puigallstar,” on his Twitter account. … The Dodgers’ game in Arizona on Monday night drew a 4.1 rating in the Los Angeles market on Prime Ticket, making it the network’s highest-rated Dodgers game since 2009.

dylan.hernandez@latimes.com

Twitter: @dylanohernandez