San Diego Padres Clayton Richard will be headed to the disabled list after feeling pain in his AC joint (down his neck and into the upper part of his chest) in Friday’s game against the Los Angeles Dodgers.Richard had only thrown two pitches (the first a ball and the second a strike to leadoff hitter Mark Ellis) before he felt discomfort in his shoulder.Padres manager Bud Black came out to meet with the southpaw, which ended with Richard being pulled from the game.Tim Stauffer came into the game in relief of Richard, pitching four innings of one run ball en route to a 5-2 victory for the Padres.Richard admitted to having felt discomfort earlier this week, but was not concerned heading into Friday’s start.“It was rough, something I hoped wouldn’t happen. I had some discomfort this week leading up to [the start], but I thought I’d be able to get through. Unfortunately, once I got going, I knew things weren’t right,” Richard told reporters after the game.Coming into the game, Richard boasted a 2-5 record and 7.01 ERA in 52 2/3 innings of work over 11 starts. Richard was coming off of arguably his best outing of a rough season, a 4-1 victory over the Arizona Diamondbacks in which he pitched eight innings of one run ball.Richard previously had arthroscopic surgery on his left shoulder in July 2011, but is confident that this injury is not related to the 2011 shoulder injury. Previously this season, Richard spent 19 days on the DL with an intestinal virus, missing the majority of the month of May.