Game 21 lineups: Nats at Rockies

DENVER - As with Joe Ross last night, tonight will be right-hander Tanner Roark's first career start at Coors Field. He has gone 1-0 with a 3.86 ERA in his last three starts. Gerardo Parra is 4-for-10 with a homer against Roark in his career. Roark is 2-0 in four starts this season with a 3.65 ERA.

Adam Eaton has now reached safely in 17 of 20 games this season and has hit safely in 13 of them. He has three hits in the series and has scored four runs.

Daniel Murphy went 3-for-5 last night with a career-high-tying five RBIs. He has done that six times, and twice this season. He had five RBIs against the Cardinals on April 11. He is batting .325.

Rockies right-hander Tyler Chatwood allowed four runs on seven hits and three walks but notched the win in his last start. Anthony Rendon is 2-for-3 lifetime against Chatwood. Chatwood is 2-2 with a 4.10 ERA this season.

Charlie Blackmon has extended his hitting streak to 10 games and is batting .331 with two doubles, two triples, five home runs and 15 RBIs in that span.

DJ LeMahieu went 3-for-4 last night for his ninth multi-hit game of the season. Mark Reynolds has hit .421 (8-for-19) with two doubles, three home runs and eight RBIs in this five-game homestand.

Baker was true to his word from earlier in the week that he would get Matt Wieters another day off. Jose Lobaton starts behind the plate tonight.

WASHINGTON NATIONALS at COLORADO ROCKIES
Where: Coors Field, Denver, CO
Game time: 8:40 p.m. EDT (6:40 p.m. MDT)
TV: MASN2
Radio: 106.7 FM, 980 AM, XM 188/869, MLB.com
Weather: 57 degrees, mostly cloudy; 15 percent chance of precipitation, winds north to northeast at 9 mph

NATIONALS (14-6)

CF Adam Eaton
SS Trea Turner
RF Bryce Harper
1B Ryan Zimmerman
2B Daniel Murphy
3B Anthony Rendon
LF Jayson Werth
C Jose Lobaton
RHP Tanner Roark

ROCKIES (14-7)

CF Charlie Blackmon
2B DJ LeMahieu
3B Nolan Arenado
RF Carlos González
1B Mark Reynolds
LF Gerardo Parra
SS Trevor Story
C Tony Wolters
RHP Tyler Chatwood