​The Dodgers hate paying inflated trade deadline prices for impact relievers.And not even an injury to one of their key bullpen arms seems probable to change that this year.Before Friday’s series-opener against the Boston Red Sox, Dodgers manager Dave Roberts said that right-hander Brock Stewart was going on the injured list with a problem in his right shoulder — the same one he had season-ending surgery on last year after arriving as a deadline acquisition.The move comes amid what’s already been an unsettling stretch from the Dodgers’ relief corps (which has a 23rd-ranked 4.90 ERA in the majors since its historic 38-inning scoreless streak back in May) and its right-handed options especially (Stewart had been the most trustworthy choice there of late, before closer Edwin Díaz returned from his own injury this week).Dodgers manager Dave Roberts said that right-hander Brock Stewart was going on the injured list with a problem in his right shoulder Charles Wenzelberg / New York PostAnd not even an injury to one of their key bullpen arms seems probable to change that this year. Getty ImagesHowever, Roberts staunchly downplayed the severity of Stewart’s latest injury; which, pending an MRI scheduled for Saturday, the skipper repeatedly insisted is expected to be short-term.“This is just more of a formality,” Roberts said, in part since it allowed the club to call up triple-A starter Cole Irvin to contribute to Friday’s planned bullpen game. “I really believe, the training staff believes, that it’s going to be short term.”According to a source with knowledge of the team’s plans, the development is not expected to change the front office’s relative lack of urgency to add to its bullpen before Monday’s deadline, either.The Dodgers have been evaluating the relief market lately, to be sure. Earlier this month, they added intriguing triple-A right-hander Seth Halvorsen from the Rockies. This week, they’ve been linked to Mets starter (and former Yankees closer) Clay Holmes. One of their potential trade partners — Tarik Skubal’s Detroit Tigers — are also shopping a veteran righty in Kyle Finnegan, who could fit the Dodgers’ apparent depth need.Internally, though, the two-time defending champions are confident in the state of their unit.However, Roberts staunchly downplayed the severity of Stewart’s latest injury; which, pending an MRI scheduled for Saturday, the skipper repeatedly insisted is expected to be short-term. Getty ImagesDíaz’s fastball has looked improved in two outings since returning from the injured list. Evan Phillips’ stuff has also played up since returning from Tommy John surgery, albeit while showing some rust with command.Edgardo Henriquez — who was the opener for Friday’s series-opener against the Red Sox — has largely been steady, despite the resurgence of some of his own command issues lately.And though Will Klein has endured a midseason slump, more help could be on the way in the for