The Instagram photo shows Justin's wife Jessica Biel holding Silas in her arms, said The Hollywood Reporter.
Silas represents his father's hometown by wearing a Memphis Grizzlies shirt in the photo.
"The Timberlakes are ready!!! GO GRIZZ! #GritNGrind #Playoffs #BabyGrizzROAR," Timberlake captioned the shot.
The couple welcomed Silas, their first child, on April 11. They tied the knot in October 2012.