Keller does a pretty good job at suppressing homers (0.86 HR/9, 9 HR/FB%) for a low K (18.2 K%), low GB (39.7 GB%) pitcher.
Even with a better K% and GB% (24.5%, 44%) and a lower BB rate (6.3% vs 8.2%), Griffin's FIP gets hit because gives up more homers on his flies (1.46 HR/9, 16.3 HR/FB%).
Pirates have scored the 3rd most runs in MLB, 18 behind the Nats. Pirates have run a much better BABIP (.320 vs .289).
Mead sitting vs the righty, as is Young. Tena DH'ng, Vivas at 3rd, Crews in CF. Nats face 3 rigthies this series, so you can expect Mead and Young to get some starts at some point.