Baker may not define bullpen roles until after opening day

VIERA, Fla. - As they enter their final week in Florida, the Nationals still are trying to establish specific bullpen roles. It would help, of course, if they already knew who exactly will be in their bullpen come opening day.

That's not the case yet, with two jobs still up for grabs even at this late date.

Given that situation, Dusty Baker hasn't been able to finalize in his mind who he'll be calling upon for certain game situations.

"We're not exactly sure where we're going to slot guys yet," the manager said. "Sometimes you won't know until you get into the season. I mean, if you knew exactly where you were going to slot everybody in your bullpen, then that means you didn't have any slots open in the first place."

What do the Nationals know for sure? Well, Jonathan Papelbon is the closer. Yusmeiro Petit is the long man and emergency starter. Oliver Perez is a left-handed specialist. Shawn Kelley and Felipe Rivero are on the team, likely holding down late-inning roles.

But that still leaves two open slots, with seven healthy candidates still in big league camp: right-handers Matt Belisle, Trevor Gott, Rafael Martin, Nick Masset and Blake Treinen; plus left-handers Sean Burnett and Aaron Laffey.

From that group, Treinen has pitched particularly well, with eight scoreless innings (and only one walk) on his Grapefruit League resume. Baker continues to talk up the hard-throwing sinkerballer, and this morning reiterated the organization is viewing Treinen strictly as a reliever right now.

Burnett also has stood out, perhaps the biggest surprise in camp. The 33-year-old left-hander, who has made only 16 big league appearances since leaving the Nationals after the 2012 season and had the second Tommy John surgery of his career in 2014, has retired 17 of the 22 batters he has faced this spring and hasn't allowed a run.

More importantly, Burnett said his arm has held up through the rigors of camp, leaving him confident his health is no longer an issue.

"It has responded much better than I thought it would, to tell you the truth," he said. "There were still question marks coming into games and what the adrenaline would be like. But the arm has responded as well this spring as it did all of last year (while rehabbing). There's no question marks, nothing in the back of my mind that says I won't be able to do it."

The Nationals face a key decision with Burnett in the next week. His minor league contract contains an April 1 opt-out clause if he's not added to the big league roster. Burnett, according to a source familiar with the situation, believes there will be interest from other clubs if he doesn't make the Nationals roster, and thus it's highly unlikely he would accept an assignment to pitch at Triple-A.

If he's on the team, Burnett would be one of the few members of the Nationals bullpen with an established track record of success in late innings. Because of that, and because he's still new to the organization and is still getting a better sense of each of his pitchers, Baker recognizes he may not be able to establish firm relief roles right out of the gate.

"You've got to remember: I haven't seen Rivero in real action," the manager said. "I've seen Papelbon. I haven't seen Rivero. I haven't seen Treinen. I haven't seen a number of these guys in real time, in real action. Which guys are going to walk the first guy? Which guys love pressure? Which guys are better starting an inning off? And which guys are terrible with runners inherited? Which guys can relish the situation with runners inherited? You've got to find some of that out, in action. I know everybody wants definitive answers, but I can't give them to you right now on March 24."