Grosicki is back at The Hawthorns after his loan move to Nottingham Forest was not ratified by the EFL.
He could still make his Premier League debut for the Baggies, with Bilic only listing 24 players in his squad after the transfer window closed – with a maximum of 25 players permitted.
“Of course he is going to be included," Bilic said. “I feel sorry for him because he is a great lad and very professional.
“We are not over-loaded with players and I said it then that the reason why we were willing to do it [let him leave on loan] was because we had to offload some players to bring some players in.
“It took a little bit longer for his case to be solved but, as I said, we are not overloaded in any positions and he is an international player who has played in the World Cup and big tournaments and very proven – he is proven in the Premier League.
“He is still in the first 11 for Poland and he is going to be included but it is entirely down to him how much he is going to play or be involved.
“But I like him as a player a lot and he is on fire when he is on top form, he is really very, very valuable for us so I am glad that he stays."