Six times this season, Washington Nationals starter Stephen Strasburg has taken the mound to begin a game and only once has he met the sky-high expectations set for him. His first-inning struggles have continued, his command has wavered at times and his aggression has been lacking.

After Monday night’s 3-2 loss to the Atlanta Braves, Manager Davey Johnson said Strasburg was dealing with tightness in his right forearm, a possible reason for his uncharacteristic four-walk performance and wavering command. Johnson said Strasburg was examined by medical staff following the game and would receive medication.

“He was still throwing good but his command was way off so I knew something was off,” said Johnson, adding it was too early to tell if Strasburg would miss his next start scheduled for Saturday. The Nationals have been cautious in the past with Strasburg, who had elbow ligament replacement surgery in 2010.

Strasburg, who shook his arm more than normal between pitches, insisted he felt fine on the mound. His said his command issues were because of a breakdown in his mechanics.

“I’m not missing my next start,” he said. “I’ll tell you right now.”

The game was ultimately lost in the seventh inning when Tyler Clippard, nursing a tie game, walked leadoff hitter Gerald Laird, who scored three batters later on a sacrifice fly by Andrelton Simmons. All three runs scored by the Braves started as leadoff walks. But Strasburg’s apparent forearm discomfort was more important than the Nationals’ fourth straight loss to their stiffest division rival.

“That overrides everything,” Johnson said. “Hopefully he’s going to be all right. We’ll just have to wait and see.”