Dodgers’ plans for pitcher Frankie Montas change

When Frankie Montas began a rehabilitation assignment four weeks ago, he appeared a lock to join the Dodgers bullpen in the very near future. But the organization’s plan for Montas changed as the big league relievers found consistency and the starting rotation continued to show signs of leakage.

So rather than aid the bullpen, where his 100-mph fastball can dust aside hitters, Montas has been groomed as a starter. On Sunday, his 30-day assignment ended, and the Dodgers reinstated him from the 60-day disabled list and optioned him to triple-A Oklahoma City.

Montas had been in Oklahoma City since May 30. He has begun to stretch himself out, and threw 60 pitches in four innings last week. Montas struck out six and walked none. His strikeout-to-walk ratio in six minor league outings is 9 to 1.

The Dodgers acquired Montas, a 23-year-old right-hander, in the three-way trade with the Chicago White Sox and Cincinnati Reds that also produced Trayce Thompson. Montas struck out 20 batters in a 15-inning cameo with Chicago last season. His integration into the Dodgers’ plans was delayed when he required rib resection surgery in January.

Montas could still join the team as a reliever later this summer. But his work as a starter adds a third arm to the organization’s roster of rehabbing pitchers. A day after Brandon McCarthy made his first rehab start, Hyun-Jin Ryu returned to action for Class-A Rancho Cucamonga.

Ryu threw 46 pitches across three innings. He gave up two runs on three hits, and struck out three. Both Ryu and McCarthy will need four more starts before they are candidates for activation.

Andy.mccullough@latimes.com

Twitter: @McCulloughTimes