San Diego Padres pitcher Matt Waldron was a saving grace for the team when Nick Pivetta landed on the injured list. The already thin starting rotation got thinner with Pivetta's departure, and the Padres needed a replacement as Griffin Canning and Joe Musgrove weren't ready to return from injury. That opened the door for Waldron, who got his chance at maintaining a permanent spot in the rotation. Things have unfurled into somewhat of a nightmare for the right-hander, however, as his latest start on Tuesday marked the 13th consecutive appearance Waldron had given up a home run . Waldron allowed six runs, eight hits and issued three walks across 2.2 innings of work. The veteran is sporting a 9.28 ERA through 21.1 innings this season. His poor performance has given team insiders reason to believe Waldron's tenure with the Padres is over. "Waldron has long battled internally over his identity on the mound — whether he is a pitcher with a knuckleball or a knuckleball pitcher.…