Who starts Sunday's first-half finale?

They haven't made any formal announcement yet, but the Nationals appear to be setting things up for Joe Ross to start Sunday's first-half finale against the Braves.

Officially, the Nationals are still deciding between Ross and Tanner Roark for the assignment.

"We don't know," manager Dusty Baker said when asked if Ross will make the start. "It just depends on if we might have to use one or the other (today). It'll either be him or Tanner."

The insinuation was that the plan could be altered if one of the right-handers was needed in relief later this afternoon. But such a scenario would almost certainly feature Roark coming out of the bullpen, not Ross.

In fact, Roark was stationed in the right field bullpen Friday night and was warming up at one point late in the Nationals' 5-4 10-inning victory.

"Tanner was warming in case we needed some length in that game last night," Baker said. "He knows how to warm up as a reliever much more than Joe."

Roark indeed has more than token relief experience in his career, with 38 of his 136 major league appearances coming out of the bullpen. Ross has only three relief appearances out of 47 total as a big leaguer, and all came at the end of his rookie season in 2015 when the organization was monitoring his workload.

This situation arose because of Wednesday night's rainout against the Mets. Roark had been scheduled to start that game, but rather than push him to Thursday's game against the Braves and thus push every other member of the rotation back a day, the Nationals elected to skip Roark and let Gio Gonzalez, Max Scherzer and Stephen Strasburg start on normal rest.

Roark's struggles - he's 6-6 with a 5.27 ERA in 17 starts - also played a role in the club's decision to skip his turn.

Ross, meanwhile, has seemingly turned a corner over the last month. After compiling a 7.34 ERA in his first six starts this season, the right-hander has bounced back to post a 2.95 ERA over his last six starts.