The crafty right-hander has put together a solid resume against Milwaukee during his career, and will look to lead the Nationals (21-26) and continue his success against the Brewers.
In 22 career starts, Hernandez is 9-6 with a 3.55 ERA against Milwaukee. His previous outing against the Brewers (25-23) came earlier this season on April 17, when he allowed just one run in seven innings to receive the win.
"[Hernandez is] always consistently low in the zone," Milwaukee center fielder Carlos Gomez said after Hernandez carved up the Brewers last month. "He kept the ball low in the zone, nothing elevated, and that's what happens. That's why he's had all of these years in the big leagues."
It won't be as easy as last time, however.
The Brewers have been playing their best baseball of the season as of late. Milwaukee enters Tuesday's game having won nine of its previous 11 games, including an 11-3 thumping of the Nationals on Monday.
The Brewers will throw left-hander Chris Narveson (2-3, 3.44 ERA) out on the mound to face Hernandez. Narveson put together one of his best starts of the season in his last outing, as he shut out the Padres for 7 1/3 innings to receive a no-decision.
Narveson has already turned in three starts in which he has thrown at least six scoreless innings.
Nationals: LaRoche heads to DL
First baseman Adam LaRoche was placed on the 15-day disabled list on Monday (retroactive to Saturday), due to a torn labrum in his left shoulder.
"Adam is basically saying, 'It doesn't hurt, but I can't believe I'm missing these pitches,'" manager Jim Riggleman said. "'So, maybe it's something there that's not allowing me to get to the ball.'
"We've got to explore that. No throwing activities, no lifting, no swinging."
Pitcher Stephen Strasburg threw his first bullpen session on Monday since undergoing Tommy John surgery on Sept. 3.
Despite trailing by several runs, Riggleman inserted Drew Storen into the game on Monday night to get his closer some work. Storen hadn't pitched in six days, and the rust showed. The right-hander gave up three runs, snapping his 21-inning scoreless streak and raising his ERA to 1.48 from 0.38.
Brewers: Marcum takes home share of NL award
Pitcher Shaun Marcum was named the co-National League Player of the Week on Monday. He delivered two wins and posted a 1.20 ERA in two starts last week. With the win over Washington on Monday, Milwaukee is off to its best home start through 23 games in franchise history, with a record of 17-6.
Milwaukee first baseman Prince Fielder has managed just two hits in 17 career at-bats against Hernandez.
The Nationals enter Tuesday's game having lost five of their previous six games.