Allardyce has paid tribute to the 23-year-old who came to help out the Baggies during their hour of need four months ago.
He said: “Ainsley's given us everything he has got.
“He came to join the fight - you have to admire that - he knew my idea was to play him where he wanted to play and where he's always wanted to play - in midfield.
“And my words to Ainsley were this: You'll play in midfield as long as you continue to play well. It's up to you whether you will hold on to that position.
“There's just one thing missing and it's something he just needs to work on - it's the same with Connor Gallagher - they need to score more goals. They need to chip in.
“They're up-and-down players, they can get box-to-box, they can get on the edge of the box, in the box, they can get chances - but if they do, they need to improve their finishing.
“It's the same for every midfielder, or every attacking midfielder like them, they have to add some goals.
“Overall, Ainsley has done the job we asked him to. He's played where we have asked him, he's played where he wanted to. He's made a big contribution. But there is just one thing missing: Those goals that we ultimately needed.
“It wasn't just about your front three but you need two or three each from your midfielders - and that could have made a big difference to us."