The online tour information service Pollstar has added a listing showing a performance by Wynton Marsalis and the Jazz at Lincoln Center Orchestra on Saturday, March 13, 2010 at the Sheldon Concert Hall.
Marsalis and the JaLCO (pictured) were in St. Louis most recently in February 2008 to perform at The Sheldon's benefit gala, which usually happens sometime in late winter or early spring.
It seems entirely plausible that they might be booked for a return appearance in 2010 at the same venue; however, listings on Pollstar should be considered unconfirmed until officially announced by the venue and/or presenter.
Still, a look at the band's tour schedule shows the St. Louis date scheduled between concerts in Germantown, TN and Minneapolis, MN as part of a tour that begins March 1 and continues through the end of the month, so I'd say this one looks likely to happen. StLJN will have more details as they become available.