Game 156 lineups: Nats vs. Diamondbacks

And so we have reached the final week of the regular season, and thus the final homestand of the regular season. Way back when, we probably figured these would be meaningful games, with the Nationals engaged in a tense pennant race down to the wire. In reality, their run to the National League East title was much easier than that, and they clinched Saturday night in Pittsburgh.

There is, of course, still something on the line this week: Home field advantage for what is now officially an National League Division Series matchup with the NL West champion Dodgers. The Nationals hold a 1 1/2-game advantage right now, with Los Angeles off tonight. The magic number to clinch home field is six.

Bryce Harper is not in the lineup for tonight's series opener against the Diamondbacks (featuring third base coach Matt Williams, by the way). Nor is second baseman Daniel Murphy. Harper jammed his right thumb in Sunday's game at PNC Park, while Murphy has not started since Sept. 17 because of a left buttocks strain.

Tanner Roark, meanwhile, is on the mound, seeking his career-best 16th win in his second-to-last tune-up before a likely Game 2 start against the Dodgers.

ARIZONA DIAMONDBACKS at WASHINGTON NATIONALS
Where: Nationals Park
Gametime: 7:05 p.m. EDT
TV: MASN, MLB.tv
Radio: 106.7 FM, XM 183, MLB.com
Weather: Chance of rain late, 68 degrees, wind 10 mph right field to left field

NATIONALS (91-64)
CF Trea Turner
LF Jayson Werth
3B Anthony Rendon
C Wilson Ramos
2B Stephen Drew
1B Ryan Zimmerman
RF Brian Goodwin
SS Danny Espinosa
RHP Tanner Roark

DIAMONDBACKS (64-91)
2B Jean Segura
3B Jake Lamb
1B Paul Goldschmidt
C Welington Castillo
LF Brandon Drury
RF Yasmany Tomas
SS Chris Owings
CF Mitch Haniger
RHP Archie Bradley

The Nationals have acquired catcher Taylor Gushue from the Pirates in exchange for infielder Chris Bostick. Gushue, 22, hit .226 with eight homers and 38 RBIs in 90 games for high Single-A Bradenton this season. He was a fourth-round pick out of Florida in the 2014 First-Year Player Draft. Bostick, 23, hit .250 with eight homers and 51 RBIs in 135 games between Double-A Harrisburg and Triple-A Syracuse this season. He was designated for assignment on Sept. 18 when the Nationals activated right-hander Joe Ross from the disabled list.