The Knicks finally have filled out the back end of their roster.

Westchester product Matt Ryan has been signed to a non-guaranteed standard deal for this season, according to a source, while rookie center Ariel Hukporti had his two-way contract converted to an NBA deal to get the Knicks to the league’s 14-man requirement by Tuesday’s deadline.

They also have signed Boo Buie, an undrafted guard out of Northwestern, to a two-way contract to essentially play with G-League Westchester.

Ryan’s deal will become fully guaranteed if he’s not waived by early January, but that gives the Knicks about two months to see how veteran guard Landry Shamet’s rehab goes from a dislocated shoulder suffered during the preseason. They eventually could waive Ryan and sign Shamet, who is hoping to avoid surgery.

The 6-foot-6 Ryan, a 27-year-old product of Iona Prep in New Rochelle, is a 41.1 percent shooter from 3-point range over 63 NBA games with four teams, including 45.1 percent in 28 appearances last season with the Pelicans.

Backup point guard Cam Payne has been listed as questionable for Wednesday’s road trip finale against the Hawks after sitting out Monday’s loss to the Rockets with a strained left hamstring. Reserve big man Precious Achiuwa (hamstring) will miss his seventh straight game to start the season.

Trae Young has been listed as probable for the Hawks after suffering a right rib strain in Monday’s loss to the Celtics. The three-time All-Star guard scored only two points on 1-for-10 shooting in 23 minutes against Boston. Young had averaged 27.0 points and 11.7 assists over the Hawks’ first seven games this season.

The Hawks (3-5) remain without Bogdan Bogdanovic (hamstring), but small forward De’Andre Hunter (knee) has been upgraded to questionable after missing the past six games.