Washington Nationals closer Sean Doolittle is looking forward to a long-awaited homecoming beginning Monday at Citizens Bank Park. The Shawnee High graduate has never played a major-league game in the Phillies' ballpark, where he used to root for the home team, first in high school and then when he would come home from the University of Virginia.

That streak will end when the Nationals begin a three-game series Monday against the Phillies.

"I am excited to play in front of some friends and family in Philadelphia," Doolittle said earlier this month in an interview before a Nationals game in Milwaukee. "I grew up a Phillies fan and watched a lot of games when I was in high school and college."

Doolittle, who was traded to Washington on July 16 from the Oakland Athletics, has faced the Phillies four times in his career, but never at Citizens Bank Park. He pitched against them twice in 2014 at Oakland and twice earlier this month at Washington. He is 1-0 with three saves, no hits, no walks and eight strikeouts in five innings.

This actually won't be Doolittle's first time competing at Citizens Bank Park. As a Shawnee senior in 2004, he played for the Burlington County team in the Carpenter Cup, the 16-team all-star tournament composed of teams from the tri-state area.

That was the first year Citizens Bank Park was open, and the Carpenter Cup semifinals and finals were held there, just as they continue to be.

His recollection of the Carpenter Cup?

"I didn't start the game, but I did really well," he said.

Doolittle, who will turn 31 on Tuesday, was correct on both fronts. He entered the game in relief and pitched three innings, the maximum amount allowed by Carpenter Cup rules.

Doolittle allowed no hits and one unearned run, while walking one and striking out five. His team lost, 7-4, to Mercer County in 10 innings and he didn't factor in the decision.

"We won the first two games at Penn to get there and were so excited to be playing in the Phillies' stadium," he recalled.

He has the same enthusiasm playing for a Nationals team that is a serious World Series contender. Doolittle played in three straight postseasons with the A's, from 2012 to 2014, but since then the team has struggled and it could finish in last place in the American League West for the third straight year.

Now he is preparing once again for the postseason, and just like his days with Oakland, he will have a prominent role. In Doolittle's first 27 appearances for Washington, he had 19 saves in 19 opportunities and a 2.00 ERA.

"Doolittle has given us stability in the closing role," Nationals manager Dusty Baker said.

Baker said Doolittle's approach to the game is as impressive as the lefthander's stuff.

"He is always paying attention and is always in the ballgame," Baker said.

Doolittle, who struck out 23 in leading Shawnee to a 5-3 win in 10 innings over Kearny in the 2003 Group 4 state championship as a junior, has thoroughly enjoyed his brief time with the Nationals.

"When teams are in the other league, you see them once every three years [in interleague play] and all you usually see is highlights on TV, but you don't have a sense how good they are," Doolittle said. "It's awesome to be on a team with so many talented players."

One of them is Doolittle, who will soak in the three-day series with the Phillies.

"I am excited to actually play there and hear it from the fans in the visiting bullpen," he said. He is well-versed on  Phillies fans' reputation for never making it easy on the visitors.

He admits that this won't be just any series. After waiting more than 13 years to return to Citizens Bank Park, Doolittle will at least briefly take some time to soak in the atmosphere.