According to Andrew Perna at RealGM, the Pacers will not fill out their roster with Marcus Williams or any other D-League player at this time.
"We've taken a close look at our options and we're not going to make a roster move at this time," Pacers general manager David Morway told RealGM via e-mail.
Hey, if the coach doesn't want another player around, might as well
Williams play in the D-League playoffs, evaluate him and other players further before filling a non-guaranteed slot in the offseason. The only risk is losing him to another team, but again, that risk is minimal considering Williams has been available for three years now.