WASHINGTON -- Rookie Aaron Altherr had four hits, including an inside-the-park grand slam and a solo homer, and the Philadelphia Phillies beat the Washington Nationals 8-2 Friday night in what might have been Jordan Zimmermann's home farewell.

The Nationals lost their fourth straight. They entered the day 7 1/2 games behind the Mets in the NL East.

Zimmermann (13-9), who will be a free agent this offseason, exited after allowing six earned runs on six hits over five innings. He suffered his first loss since Aug. 12.

Philadelphia starter Jerad Eickhoff (2-3) won for the first time since his Aug. 21 major league debut, giving up two runs on five hits while striking out 10.

Altherr had four hits and legged out his grand slam when center fielder Michael Taylor whiffed diving for a sinking liner in the third.

Altherr hit the first inside-the-park grand slam in the majors since 1999, when Tampa Bay's Randy Winn did it, according to the Elias Sports Bureau. It was the Phillies' first inside-the-park homer since July 31, 2012, when Jimmy Rollins hit one.

"Just a good day I guess,'' said Altherr, trying to explain his exceptional 33rd big-league game. "Put the bat on the ball and good things happen.''

Phillies manager Pete Mackanin was asked if he'd ever seen an inside-the-park grand slam.

"I'm sure I have over 47 years,'' he said. "But I can't remember. I hit into a triple play once.''

Zimmermann's 70 wins are the most by a National since the franchise moved to Washington.

"Feel like I took the ball every time they asked, did what I could,'' he said of his career in Washington. "Some days I didn't have it, some days I was good.

"I'm not saying this is my last start. You don't know what's going to happen this offseason, so we'll see.''

Zimmermann's 2015 regular season home finale was less memorable than a year ago, when he tossed a no-hitter on the final day of the season. He did, however, receive a warm ovation from the crowd when he walked in from the bullpen prior to the game.

"It was awesome,'' he said. "It means a lot to me, and I just wish I could have gave them something a little better than that.''

Information from The Associated Press was used in this report.