Stephen Strasburg relaxed on a black couch in the Nationals clubhouse Tuesday afternoon, chatting with catcher Kurt Suzuki. If there was any lingering concern over the forearm tightness he was feeling the previous night in a 3-2 loss to the Atlanta Braves, the right-hander didn’t show it. This afternoon, the discomfort was gone. The Nationals insisted that Strasburg was healthy and what he was feeling was only irritation. General Manager Mike Rizzo said Strasburg’s right arm was “structurally perfect,” and added that the team’s No. 1 starter was expected to make his next start Saturday in Pittsburgh. Strasburg, whose right elbow underwent Tommy John surgery in 2010, was evaluated by the Braves team physician at Turner Field and given a clean bill of health, Rizzo said. No further tests were scheduled, he added. “He’s healthy, happy and ready to pitch Saturday,” Rizzo said. Manager Davey Johnson suggested that the irritation stemmed from a muscle-stimulation machine that Strasburg used prior to his start in Atlanta. After saying Monday night it was too early to tell if Strasburg’s discomfort would keep him from making his next start, Johnson said he wanted to see how Strasburg’s arm feels following his bullpen session Wednesday. But the manager said he was no longer worried about Strasburg and anticipated him taking the mound in four days. “Stras feels a lot better about it, so do I,” Johnson said. Part of Johnson’s original concern was Strasburg shaking his arm in between batters, a practice Strasburg stopped doing but said Monday he did again to help keep his arm loose. Strasburg’s wildness — four walks and only 50 of his 93 pitches for strikes — was also a tip-off for Johnson. On Tuesday, both Johnson and pitching coach Steve McCatty explained that Strasburg’s stumbles were relatively small and more of a mental hurdle. “His mechanics are fine,” Johnson said. “Again, it goes back to wanting to do too much. He’s a perfectionist and the pitch he wants to be perfect. Sometimes he’ll try to put a little extra instead of just hitting his spots and just pitching.”