The Capitals got LeBlanc from Chicago in exchange for future considerations. The 24-year-old has four goals and eight assists in 34 games this season with Rockford of the American Hockey League.
Wellman came over in a deal with Florida, which received centre Zach Hamill in the swap. The 25-year-old Wellman has seven goals and 16 assists this season with San Antonio of the AHL.
Hamill has 11 goals and 11 assists this season with Hershey of the AHL.
The trades were announced Thursday.