DENVER – Justin Upton's at-bats have become must-see viewing, not just for Braves fans but teammates.

They say they make sure not to be using the restroom or otherwise occupied when Upton comes to the plate. The left fielder is hitting .316 with a majors-leading 11 home runs and a National League-leading .797 slugging percentage in his first 21 games for the Braves.

“Just stand away, don’t say anything, let him keep doing what he’s doing,” Braves shortstop Andrelton Simmons said. “You make sure you watch him. Him and (Evan) Gattis. For me, him and Gattis, those are the strongest guys on the team and it’s pretty fun when they catch one. I don’t miss it.”

Gattis said of Upton’s at-bats: “I’m always paying attention. It’s fun to watch, man.”

Upton’s two homers in Tuesday’s doubleheader gave him a Braves-record 11 homers in April and left him just two shy of the major league record of 14 homers in April, done by St. Louis’ Albert Pujols in 2006 and matched by the Yankees’ Alex Rodriguez in 2007.

The Braves have five games left in April, three at Detroit starting Friday and the first two games of a four-game series against the Nationals. Upton has started all 21 games for the Braves so far in his first season with the team, and they have an off day in the schedule Thursday.

Upton topped the franchise record record of 10 homers in April, done twice by Andres Galarraga (1998 and 2000) and once by Ryan Klesko (1996).

His 10th homer came in the first game of Tuesday’s doubleheader, the Braves’ 19th game. That was the fastest any Brave has ever hit 10 homers, one game quicker than Dale Murphy did it in 1985. Upton homered again in the nightcap.

Justin has hit a home run in each of the three games that brother B.J. has homered in for the Braves this season. According to the Elias Sports Bureau, the Uptons are the first brothers to homer for the same team in the same game three times in a single month.

In fact, the only other brothers who’ve ever done it as many as three times in an entire season were another pair of Braves, the legendary Hank Aaron and brother Tommie, in 1962.