The loss evened Gonzalez's record to 4-4 with a 4.82 ERA.
Nationals manager Matt Williams said Gonzalez couldn't throw the ball where he wanted to throw it.
"He got behind hitters, lost command of the strike zone. He didn't have any command at all today. He has to work on that," Williams said. "Everything was up, everything was middle, he didn't hit any corners. The ball wasn't down."
Gonzalez is known to make adjustments on the fly during games, but he was unable to stem the tide on Monday. He didn't have any excuses after the game. He said he was inconsistent in the strike zone.
"I was falling behind and trying to get back in the strike zone. [The Rays] were putting the ball in play," Gonzalez said. "They found holes, they found hits, they found a way to get a run in. I was trying to make adjustments, just trying to pound the strike zone. Obviously, it wasn't working. I walked too many guys. I have to do a better job."
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the Time. He also can be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.