BALTIMORE -- The Nationals have to make a decision on who will be their starter against the Braves on Tuesday. Washington has already decided it will not use a bullpen-by-committee.

Washington manager Jim Riggleman declined to say who would start, because someone on the 25-man roster will be affected. The team has eight relievers so one of them will be taken off the roster. It will be a tough choice because all of the relievers are doing a good job.

As far as the starter goes, right-hander Craig Stammen and left-hander Matt Chico are candidates to get the assignment for the Nationals. Stammen has improved since he was optioned to Triple-A Syracuse in early June. In three starts, Stammen is 2-0 with a 2.25 ERA for the Chiefs.

Chico is having a respectable Minor League season, going a combined 4-5 with a 3.36 ERA for Double-A Harrisburg and Syracuse.

Left-hander John Lannan is not candidate and is expected to get another start in the Minor Leagues. The team wants Lannan to get his confidence back before he returns to the big leagues.

Guzman scratched with stiff neck

BALTIMORE -- Nationals second baseman Cristian Guzman was scratched from the lineup in Sunday's 4-3 loss to the O's, because of a stiff neck. Instead Adam Kennedy, who went 2-for-4, received the start.

Manager Jim Riggleman said Guzman was expected to get treatment throughout the game. The veteran hopes to return to the lineup on Monday against the Braves.

Guzman found himself in a slump entering Sunday's action. He was 25-for-107 (.234) in his past 27 games to lower his batting average from .345 to .297.