Nationals left-hander Gio Gonzalez threw a bullpen at Nationals Park during Thursday’s off day, according to a baseball source, and the session went without a hitch.

Gonzalez next move will be having a simulated game Sunday and then have a rehab assignment five days later. It’s not known which Minor League affiliate he will play for.

The Nationals placed Gonzalez on the 15-day disabled list on May 18th because of left shoulder inflammation. Gonzalez has been dealing with shoulder problems dating back to his April 23 start against the Angels, but he said it was nothing to be concerned about. However, he had one of his roughest starts on May17th in a 5-2 loss against the Mets, allowing five runs in three innings.

After the game, he declined to discuss his shoulder problems, saying he had to gut it out on the mound. Gonzalez was placed on the DL the next day.