For the second time in three weeks, the Houston Astros nullified a minor-league option after discovering the demoted pitcher had an injury. This time it is right-hander Mike Burrows, one of general manager Dana Brown’s biggest acquisitions of an offseason that is not aging well.The team placed Burrows on the major-league, 15-day injured list Monday with what it described as right elbow neuritis. The Astros offered no timetable for Burrows’ return or other specifics about the injury. According to the Florida Orthopedic Institute, neuritis can be inflammation or compression of the ulnar nerve.Burrows was demoted to Triple-A Sugar Land on Tuesday, but he will have his option nullified and his injured list stint start from that date instead. Burrows is not eligible to come off the injured list until July 22.Burrows’ absence does not alter the Astros’ trade deadline approach — they are still prioritizing a left-handed outfield bat — but may increase the urge to find pitching help. At the very least, Burrows profiled as depth that could have helped in the rotation if he made appropriate adjustments at Triple A.Houston optioned Burrows amid a brutal start to his Astros career. He posted a 5.99 ERA across 94 2/3 innings, required a brief detour to the bullpen for a “breather” and allowed 21 home runs in 18 appearances. His nadir came in a start at Nationals Park on July 6, when he squandered a five-run lead and surrendered 10 runs.Brown parted with two touted prospects, right-hander Anderson Brito and outfielder Jacob Melton, to acquire Burrows in a three-team trade with the Pittsburgh Pirates and Tampa Bay Rays in December. At the time of Burrows’ acquisition, Brown proclaimed that he could be a future pillar of Houston’s rotation.Upon demoting him last week, Brown said: “It’s difficult because we feel like he’s a big part of our future. But we have to get more action in the (strike) zone to his stuff.” Brown also mentioned “uncharted territory” for Burrows, who has never thrown more than 128 1/3 innings in his professional career.Asked about that workload after his start against the Nationals, Burrows said: “I actually feel good. I know I’ve thrown a good amount of innings, but I feel good at this point. Nothing bad to say about that.”Burrows’ situation has some parallels to that of Kai-Wei Teng, another of Brown’s offseason acquisitions who required a minor-league demotion last month. Teng, like Burrows, seemed on pace to shatter his career high in innings pitched. Manager Joe Espada said the team demoted Teng, in part, to conserve his innings.Three days after demoting Teng, the team nullified his option and placed him on the injured list with a right knee sprain. Espada said team officials learned of the injury after Teng’s demotion and that it would not interrupt his throwing program. Teng is at the team’s complex in West Palm Beach, Fla., completing rehab.Because Burrows’ injury is to his arm, it stands to reason things will not be as straightforward.Burrows’ injury now means four of Brown’s six offseason, major-league pitching acquisitions — Burrows, Teng, Tatsuya Imai and Nate Pearson — have spent time on the injured list. The two others, Ryan Weiss and Roddery Muñoz, were designated for assignment and are no longer on Houston’s 40-man roster. The sextet has a 5.73 ERA across 260 2/3 major-league innings.