The Holland midfielder or right-back has been sidelined since late December with a toe injury.
Fabian Hurzeler declared him ready to return as his side prepare for the FA Cup fourth-round tie at Liverpool on Saturday (8pm).
He also said there were no new injuries.
Albion headed to FA headquarters at St George’s Park after Wednesday night’s 1-0 defeat at Aston Villa.
Hurzeler said: “No new injuries. Mats Wieffer will be back so that’s a positive one.
“He’s a big player with a big impact on our game. Big personality as well.
“So definitely we missed him and we're all happy that he's back now.”
Jan Paul van Hecke went off after an hour of the game at Villa Park in a pre-planned move.
He had been sidelined by a minor hamstring issue which ruled him out against Crystal Palace.
The Holland centre-back is available to start at Anfield.
Yasin Ayari continues to do rehab on a shoulder injury.
Hurzeler said: “We expect him to be back soon.”
Jason Steele impressed in goal in the third-round win at Manchester United and the expectation will be that starts at Anfield.
Hurzeler confirmed at Villa Park that Kaoru Mitoma and Yankuba Minteh are not at peak fitness.
He said: “We have to deal with it at the moment.”
The possibilty of a wide role at some stage for Charalampos Kostoulas has not been ruled out.