You can see Edwin Jackson bouncing up and down in the mosh pit. He’s yelling, pointing at the Cubs and being restrained by Nationals bench coach Randy Knorr. The full-scale brawl nearly erupted after Lendy Castillo threw inside and almost hit Bryce Harper. The Cubs had a Rule 5 pick on the mound, while the Nationals had to protect their Sports Illustrated cover boy, “Baseball’s Chosen One.” That four-game sweep in Washington last September exposed the huge talent gap. The Cubs were outscored 31-10, leading manager Dale Sveum to call it “one of the biggest butt-whoopings I’ve ever gotten in my career.” That moment showed the edge and attitude you need to play at that level. Cubs catcher Steve Clevenger pushed Michael Morse and got suspended. Pat Listach and Bryan LaHair tried to keep the peace and separate Jackson from the Cubs. Washington manager Davey Johnson barked at Jackson, who was described as “very hot” by the MASN broadcast crew, which sounded like total homers scolding the Cubs: “That’s just plain embarrassing for your whole organization.” When Jackson was asked about his role in the Sept. 6 “brouhaha” at Nationals Park, he hedged before going with “peacemaker” when a reporter mentioned the word. “Somehow I end up in the middle,” Jackson said Tuesday, “regardless of whether I’m doing anything or not.” That pretty much sums up Jackson’s entire career. This is the guy who was drafted by the Dodgers as an outfielder out of Shaw High School in Georgia and wound up pitching for seven teams across the past eight seasons.