The Capitals also assigned defenceman Karl Alzner to AHL affiliate Hershey on Wednesday.
Steckel has two goals and three assists and leads the NHL with a 61.9 winning percentage on faceoffs this season. It's the forward's third full season with the Southeast Division-leading Capitals.
He had career highs with eight goals and 19 points last season.
Sloan has two goals and two assists in his second NHL season, getting playing time at both defenceman and forward.