''Everything went well,'' Nationals manager Matt Williams said. ''The nerves were not affected. Everything seems to be OK.''
Ramos, the team's No. 1 backstop, was placed on the 15-day disabled list, retroactive to April 1. Washington recalled switch-hitting catcher Sandy Leon from Triple-A Syracuse before the second game of the season against the New York Mets.
Jose Lobaton was behind the plate Wednesday night, and Williams said choosing his starter at catcher will now be ''a day-to-day process.''
Ramos batted cleanup on opening day and felt pain in his hand on a swing. He came out of the game in the seventh inning and was sent to see a hand specialist Tuesday before having surgery Wednesday in Baltimore.
It was unclear if Ramos got hurt on a particular pitch or if the injury developed over time.
''We don't know whether it started out as a stress fracture or what,'' Williams said. ''It's rough to go through something like that, but what can you do now except rehab? He's focused on that.''
The 26-year-old Ramos batted .272 with 16 home runs and 59 RBIs in only 287 at-bats over 78 games last season. He missed 59 games with a hamstring injury.
After finishing fourth in 2011 NL Rookie of the Year voting, Ramos has had a difficult time staying healthy. He played only 25 games in 2012 because of a right knee injury that required two operations.
In a much more serious matter, Ramos was kidnapped in his native Venezuela and held for 51 hours in November 2011 before government forces freed him. Fortunately, he was given a clean bill of health after the ordeal.
''He worked really hard in spring. He worked really hard all winter. You know, even outside of baseball it's been rough on him. So I feel for him,'' Williams said. ''When he does play, when he's healthy, it's really, really good.
''Something like this you can't plan for. It happens. So all we can do is get him back as soon as we can get him back and we'll go from there.''
Williams said the Nationals considered keeping Leon on the big league roster at the end of camp.
''Sandy certainly played well in spring training,'' Williams said. ''I first and foremost love his defensive prowess. I think it's important for our club.''