Frankie Montas signed autographs with Yasiel Puig at FanFest in January. (Jon SooHoo/Los Angeles Dodgers)

Frankie Montas signed autographs with Yasiel Puig at FanFest in January. (Jon SooHoo/Los Angeles Dodgers)

By Jon Weisman

Right-handed pitcher Frankie Montas, who seemed to moving fast toward at least a temporary spot in the Dodger starting rotation a week ago, has re-aggravated a stress reaction in his rib, the Dodgers said today.

The team added he will undergo further diagnostic testing, and no timeframe has yet been given for his return.

The 23-year-old Montas, who missed the start of the 2016 season because of surgery to remove a rib in February, has 22 strikeouts in 16 minor-league innings since his return, with a 2.25 ERA. He fanned 20 in 15 innings after making his MLB debut last year with the White Sox, before he came to Los Angeles in the trade that included Trayce Thompson and Micah Johnson.

Side note: Ross Stripling is back in action, throwing three innings in an Arizona League game Thursday.