In May 2011, Rizzo was disciplined by MLB after he verbally confronted umpires in a stadium tunnel following a loss to the New York Mets.
The Nationals also placed outfielder Jayson Werth on the 15-day disabled list on Tuesday, a day after Werth underwent surgery to repair his broken left wrist. Werth is expected to be out at least 12 weeks, a huge blow to a team currently atop the NL East.
"He's been playing great," manager Davey Johnson said before Tuesday night's 5-4 loss to host Pittsburgh Pirates. "He's a team leader, swinging the bat good, doing everything good. We're going to miss him."
Werth was hitting .276 with five doubles, three homers and 12 RBI in 27 games with Washington before injuring the wrist while trying to make a sliding catch against the Phillies on Sunday night.
The Nationals did get some good news on Tuesday, activating third baseman Ryan Zimmerman from the DL. Zimmerman hasn't played since April 20 due to right shoulder inflammation.
Werth's injury means rookie outfielder Bryce Harper will remain with the team. The No. 1 overall pick in the 2010 draft started in Werth's spot in rightfield on Tuesday, going 1-for-4 with a run scored.
The Nationals took a 4-3 lead in the top of the nine on Adam LaRoche's two-run homer. But Rod Barajas answered with a two-run dinger with two outs in the bottom of the inning and the Pirates walked off with the win.
In other games *
At Houston, Pinch-hitter Brian Bogusevic hit an eighth-inning RBI double and the Astros ended the Miami Marlins' season-long seven-game winning streak with a 3-2 victory.
The game was tied at 2-2 when Travis Buck singled with two outs before Bogusevic's hit off Ryan Webb (1-1) to the corner of leftfield, which a leaping Logan Morrison just missed, sent Buck home.
* At Chicago, Dan Uggla hit a tiebreaking two-run single in the eighth inning and the Atlanta Braves beat the Cubs 3-1 Tuesday night.
* At Milwaukee, Aramis Ramirez hit a three-run triple and Yovani Gallardo (2-3) gave up two runs in six innings and tied his season high with eight strikeouts as the Brewers defeated the Cincinnati Reds, 8-3.
* At Phoenix, Carlos Beltran homered in his first two at-bats, including a grand slam, matching his career high with six RBI, and the St. Louis Cardinals beat Arizona, 6-1, handing the Diamondbacks their fourth loss in a row.
Jerry McMorris, one of the Colorado Rockies' original owners, has died, the team announced in a statement.
The team said that McMorris died Tuesday in Denver of cancer. He was 71. He served as chairman, president and CEO of the team until 2001 and was part of the team's ownership group from 1992-2005.
* Major League Baseball would fund scholarships and exert greater influence over Division I college baseball if a proposed and unprecedented partnership with the NCAA becomes reality. The NCAA, MLB and players' union confirmed preliminary discussions have been held, most recently last month in New York.