The wobbly Los Angeles Angels rotation has been seeking a salve, if not a savior. Not since Aug. 28 has an Angels starter completed six innings, and manager Mike Scioscia has been running through so many pitchers — and American League-record 12 on Monday and 43 in the last five games — that the club added two to the roster Tuesday, with a third one getting activated Wednesday. Garrett Richards won’t play the role of a one-man rescue squad, at least not for a while. He was sidelined for too long, and the time remaining in the season is too short, for him to reestablish himself as the staff ace. But the signs of that capability were on display again Tuesday, exactly five months after Richards’ last start, and the Angels will gladly take any help he can provide as they pursue their second playoff berth in eight years. Richards fired several 96-97 mph fastballs among his 52 pitches and allowed one run in 3 1/3 innings as the Angels surged to second place in the wild-card race with an 8-7 victory over the Oakland Athletics. Ben Revere’s pinch-single in the 10th inning drove in the go-ahead run for Los Angeles, which played its fifth consecutive game lasting at least three hours and 49 minutes — this one went 4:12 — a major league first.