Series preview: Nationals at Cubs

All games on WSCR-AM 670.

Season series: 2-2.

Friday: 1:20 p.m., WGN-9.

RH Tanner Roark (8-7, 4.93) vs. RH Kyle Hendricks (4-3, 3.80).

Saturday: 1:20 p.m., ABC-7.

TBA vs. RH John Lackey (8-9, 4.87).

Sunday: 1:20 p.m., CSN.

TBA vs. LH Jon Lester (8-6, 3.96).

Storylines: The Nationals' rotation is...