D-Backs place closer Martinez on IL with UCL sprain

The Arizona Diamondbacks placed closer Justin Martinez on the 15-day injured list with a sprained right ulnar collateral ligament, the club announced Tuesday.

Diamondbacks manager Torrey Lovullo said Martinez is heading for a second opinion on the injury, according to Nick Piecoro of The Arizona Republic.

Martinez exited Monday's win against the Seattle Mariners with tightness in his pitching elbow after his velocity dropped in the ninth inning.

"My elbow was getting tight in the last few pitches, and I decided to call the trainer out to figure out what was going on," Martinez said, according to MLB.com's Steve Gilbert.

Martinez missed just over three weeks in May due to shoulder inflammation.

The 23-year-old owns a 4.11 ERA with five saves and 22 strikeouts across 15 1/3 innings this season. Martinez signed a five-year, $18-million contract extension in March.

Veteran right-hander Shelby Miller filled in as Arizona's closer during Martinez's last IL stint and could get the first opportunity in the ninth inning again.