When Catherine Foster twisted her leg during a dress rehearsal for the Washington National Opera’s “Ring” last week, everyone approached the injury with an excess of caution. She would, it was said, be perfectly fine if she simply rested for a few days. So great was the caution that for the dress rehearsal of “Götterdämmerung,” Foster sang from the wings while someone else enacted the role on stage.

But caution was not enough to get Foster fit for curtain time. WNO announced this morning that Foster will not be singing “The Valkyrie” (as the company calls it) on Monday night.

In her place: Christine Goerke, the reigning American Wagnerian, last heard in DC in “Florencia en el Amazonas” — and fresh off a performance of “Siegfried” at the Houston Grand Opera last night.

[Christine Goerke talks about singing.]

Given recent news about artists performing through pain — Anne Akiko Meyers played two performances with the National Symphony Orchestra with a broken foot last week — the decision regarding Foster is, to a certain extent, bucking a trend. Joyce DiDonato, after all, sang “The Barber of Seville” from a wheelchair after gamely soldiering through after breaking her own ankle a few years ago. At issue, though, is opening night of an important production for WNO — a production that requires a certain amount of mobility. A press spokesman for WNO said that Foster’s decision to withdraw was jointly arrived at by Foster, her medical team, and WNO’s artistic director and the director of the “Ring” production, Francesca Zambello.

The audience is unlikely to be very unhappy at the announcement. Indeed, it only adds luster to the production to feature the Wagner soprano du jour. Since Nina Stemme is taking over the role for Cycle III later this month, this means that diehard fans can hear three of today’s most feted Brünnhildes, including Foster, right here in DC.

Foster is slated to return on Wednesday for “Siegfried,” which, the spokesman pointed out, doesn’t require as much movement.