The Manchester United midfielder arrived at Albion in the summer - with the Baggies beating off competition from a host of Championship clubs to land the 21-year-old.
He already came to Albion highly rated - having made a handful of appearances for United's first team.
At one point in the summer he was tipped to stay at Old Trafford and make a challenge on Ruben Amorim's first team squad.
However, the loan came and Collyer arrived at Albion.
In glimpses early on from the bench he looked to have real quality - but his first start did not come until early October against Millwall.
That was a disappointing 3-0 defeat - and he had to wait for his chance again against Preston later in the month.
But after all that waiting for a home start he came off shortly before the hour with a muscle injury - only returning as a substitute before the latest international break against Oxford United.
Having recovered, the way was paved for a big return ahead of Albion's derby clash with Birmingham City on Wednesday night.
Jayson Molumby's dismissal in the defeat to Coventry saw the international banned - with Collyer coming in to take his place in what could have been a big chance to stake his claim in the side.
However, after showing some good signs early on, the midfielder was dealt a cruel blow as he pulled up with what looked like another potential injury after just ten minutes.
It was the latest big of bad luck for a player who West Brom are yet to see the best off.