Hamels, among the league leaders with a career-high 195 2/3 innings pitched, declined to discuss the topic with reporters Monday. Previously, he has confessed he might benefit from additional rest, especially late in the season.

Two weeks ago, the Phillies chose to give Hamels an extra day of rest rather than leaving him on his normal turn to face the rival Mets. This time, though, pitching coach Rich Dubee seemed to be in favor of using Hamels against the Mets.

But Hamels will start Tuesday night against the Nationals, and Dubee said his performance may determine if he pitches Sunday in New York or is held until Monday against the Marlins at Citizens Bank Park.

"If he has an easy go and doesn't have to push it too far, we'll think about it," Dubee said. "We've got five days. We'll see how he feels. You'd like to go with your horse every five days, if possible. But, again, we have to find out where he is physically."

Hamels has faced the Mets only once this season and not since April 18, when he allowed five runs (four earned) in seven innings of a 6-4 loss. But Hamels has a 2.04 ERA over his last five starts, and overall, he's 11-8 with a 3.13 ERA in 28 starts.

If Hamels prefers to pitch Monday, Kendrick would start against the Mets. Kendrick is 1-3 with a 9.14 ERA in his last five starts.

NATIONALS 7, PHILLIES 4: Kyle Kendrick permitted six runs in four innings to put the Phillies in an early hole en route to a series-opening loss on Labor Day in Washington. The Phillies mustered only four hits and lost for the third time in four games against starter Tim Redding.

Jimmy Rollins homered in the ninth inning. Matt Stairs, acquired in a trade last week with Toronto, made his Phillies debut and went 0-for-2. The Phillies fell to two games behind the Mets in the NL East.