Shumpert, whose delayed season debut comes after having major knee surgery last may, can give the Knicks two things they currently lack: a defensive boost and youthful exuberance. Shumpert is the youngest Knick by nearly 5 years. Four players on the current New York roster made their N.B.A. debut before Shumpert celebrated his seventh birthday. With Raymond Felton out with a broken finger, Jason Kidd has assumed the bulk of the point guard duties. Kidd, who will turn 40 before the regular season ends, is fourth on the team in total minutes played. Shumpert will provide much needed depth, which would result in more rest time for Kidd.