The Europa League finalists welcome Royale Union Saint-Gilloise to Ibrox this evening, trailing 2-0 from the first leg of the third round clash.
Rangers know they have to win by two goals to take it to extra-time or by three goals to secure passage to a play-off clash with either PSV Eindhoven or Monaco.
Manager Giovanni van Bronckhorst confirmed Kent, who missed the first-leg as well as the weekend’s 2-0 win over Kilmarnock in the Scottish Premiership, is back in the squad along with Fashion Sakala.
For McCoist, Kent adds a different element to the team capable of opening games up with his ability at taking on opponents.
During his time at Ibrox, the former Liverpool starlet has contributed to 19 goals in Europe, whether it is through scoring, assisting or being fouled in the penalty box.
"We've got to play a lot better, they will play a lot better,” McCoist said on talkSPORT.
"It's a real boost that Ryan Kent could play, he's back in the squad, back training, he's key for Rangers, I think, still continues to be key for Rangers.
"He's the one player, certainly in the Rangers team, who has something a little bit different, in a one vs one situation. He can drop his shoulder and go by somebody. Once he goes by people things can open up and hopefully that's the case tonight.”
Meanwhile, Rangers know they will be ensured of Europa League group stage football if they fail to overturn the first-leg deficit.