The two will go head to head in the series opener between the Nationals and Reds on Friday at Great American Ball Park.
Leake, 0-4 with a 5.97 ERA this year, pitched fairly well in his most recent outing, against the Pirates on Saturday, but is the only member of the Cincinnati rotation who hasn't gotten in the win column. He surrendered two costly homers against the Pirates.
"It was definitely a step in the right direction," Leake said after that start. "Even though I had four walks, I was still happy with the way I threw the ball. I had a couple more mistakes than what showed, but they made me pay for two of them."
Gonzalez, meanwhile, has been a part of what is arguably the best rotation in baseball. He's 3-1 with a 1.72 ERA for the Nationals, who entered Thursday with a quality start from their rotation in 15 of 16 games dating back to April 20.
The lefty, who came over from Oakland in a December trade, scattered four hits and one run over seven innings in a victory against the Phillies his last time out.
"He located pretty good," Phillies outfielder Hunter Pence said. "He obviously has good stuff to have had the success he's had. I had some pitches to hit that I just fouled off. That's baseball. I took a good pass at him, got him one time, he pitched out of it. He has that stuff to get out of jams."
Nationals: Close calls
Entering Friday, the Nationals are tied for the Major League lead with 15 one-run games and nine one-run victories.
They are 8-0 in one-run games at Nationals Park, but just 1-6 in such contests away from Washington.
The Washington pitching staff has held opponents to a Major League-low 93 runs scored.
Thursday's 4-2 win in Pittsburgh snapped a six-game road losing streak for Washington.
Reds: The 'pen is mighty
Over the last 17 games, the Reds' bullpen has posted a 1.74 ERA. Over the last 10, the ERA drops to 0.91.
The Reds are 5-0-1 in their last six series.
Scott Rolen, who is tied with Babe Ruth for 48th on baseball's all-time doubles list, with 506, needs four to tie Rickey Henderson for 47th.
The Nationals took three out of four when the two teams met in Washington from April 12-15, narrowly outscoring the Reds, 14-12.