Perhaps the fans boo because Werth has hit so well here since joining the Nationals. That continued on Monday, when he hit a solo home run in his first at-bat to help lead Washington to a 4-0 victory over the Phillies.
Werth has called Citizens Bank Park his favorite ballpark in which to hit, citing the batter's eye in center field for being flat and close as reasons. The results back up that sentiment. He has 11 homers and 29 RBIs in 29 games here since the start of the 2013 season and has hit .291 overall in his career.
Werth has found his home run swing lately. Manager Dusty Baker noticed it during batting practice on Monday as he watched Werth launch low line drives into the stands hours before the game. The homer was his seventh this month, tied for the most in any calendar month since he signed with the Nationals in 2011.
"Home runs come in streaks, and home runs come with a thought process," Baker said. "When you start hitting a couple home runs, it's sort of like you think about it. ... So you know me, I always feel that water seeks its own level. J-W is healthy this year, where he wasn't last year, and he's always hit the ball out of the ballpark."
It was not always a given that Werth would turn into a productive player this season, considering he turned 37 in May and was hampered by injuries all of last season. But after a slow start at the plate, he has found a groove, raising his batting line to .251/.344/.445 with 19 homers.
"I've just kind of always been that second-half type of player, where the weather warms up and the season goes on and I find my groove," Werth said. "I think everybody kind of has a way to go about it, and that's just how I've been able to do it. I don't think there's any rhyme or reason to it, it's just how it is."
Jamal Collier covers the Nationals for MLB.com. Follow him on Twitter at @jamalcollier. This story was not subject to the approval of Major League Baseball or its clubs.