The 22-year-old has been struggling with a hamstring injury which kept him out for close to three weeks at the beginning of January.
The former Middlesbrough man felt some soreness in his hamstring in only his second game back against Hull last weekend and as a precaution was an unused substitute for the FA Cup replay against Burnley in midweek.
Morrison knows the importance of Saturday's clash, with just two points separating the bottom of the table Baggies from Newcastle in 15th.
"I should be ok to play despite my hamstring tightening up against Hull," he told the Express and Star.
"I didn't come on against Burnley in the FA Cup really as a precaution. It's just best to get a few more days rest.
"If I needed to come on I could have, but it was in everyone's best interests that I stayed on the bench.
"After the weekend we have got a two week break to rest up before the next game."
BackingThe Baggies were knocked out of the FA Cup by Championship side Burnley on Tuesday after manager Tony Mowbray fielded a weakened side, but Morrison has backed his boss' decision.
"The injury list is still rather big and the manager was right to make changes against Burnley," he added.
Despite Mowbray guarding against any further injuries against the Clarets, loan signing Jay Simpson was forced off in the first-half with a hamstring complaint.
"Jay got injured on Tuesday and if he doesn't make it on Saturday it will be a massive blow for us," he declared.
A win at home to fellow strugglers Newcastle on Saturday could see Mowbray's men move as high as 14th in the table and the midfielder is in confident mood.
"We are at home and we are always confident when we play at home. We believe we can win on Saturday," he confirmed.