Strasburg lasted just two innings — the shortest start of his career — in the Nationals' 3-2 victory over the Atlanta Braves on Friday night.
The right-hander grimaced after throwing a changeup to Brian McCann, the sixth batter he faced, with one out in the second inning.
Strasburg retired McCann on a grounder and struck out Dan Uggla to end the inning.
Craig Stammen relieved Strasburg to begin the third. He allowed two hits and one run — a homer by Freddie Freeman — with no walks and two strikeouts.
Strasburg threw 23 of 37 pitches for strikes.
Washington shut down Strasburg on Sept. 7 last season to limit the workload on his surgically repaired arm, keeping him out of the NL playoffs. The top pick in the 2009 amateur draft, he underwent elbow ligament-replacement surgery on Sept. 10, 2010.
The 24-year-old Strasburg was making his 12th start of the season. He began the night 3-5 with a 2.49 ERA and 71 strikeouts in 72 1-3 innings.
After getting off to a slow start this year, Strasburg was 2-0 with a 1.17 ERA in his previous three starts.