Free agent forward Robert Covington and the Philadelphia 76ers progressed toward finalizing a multi-year contract this week, but a deal has deteriorated as the two sides failed to agree upon contract length, league sources told RealGM.

Without an NBA deal, Covington is expected to sign a contract in the NBA Development League on Thursday, where several organizations plan to monitor the 6-foot-9 forward. The 76ers had offered Covington their standard, four-year proposal, with high contract guarantees, and both sides couldn’t agree to a shorter-term deal.

Covington was formally waived by the Houston Rockets over the weekend, despite being informed of a parting with the franchise early in October.

An undrafted prospect out of Tennessee State, Covington had a breakout season in the D-League a year ago, averaging 23.2 points, 9.2 rebounds and 2.4 steals for Rio Grande Valley and winning several awards (All-Star Game MVP, All D-League First Team).

He averaged 2.3 points and 4.8 minutes in seven regular-season appearances for the Rockets.

Semaj Christon will start his professional career by signing in the NBA D-League with the Oklahoma City Thunder's affiliate, the Blue.

Christon, who was the 55th overall pick in the June NBA Draft, will play multiple times a week in the D-League.

Christon played NBA Summer League ball with the Thunder in Orlando in July and has been with the franchise since he was drafted.

Christon played his college basketball at Xavier.