Since his return from QPR at the end of last month he has made one substitute appearance against Wolves and scored the opener in Albion's 3-0 training match victory over League One play-off hopefuls Peterborough on Tuesday.
"He's working well in training and did well in the reserves game the other day," he insisted to the WBA website.
"He's doing his very best to convince me and everyone else at the club that he's a player we should get behind and use more.
"I haven't reached any strong conclusions yet and it's going to be very difficult for me to reach strong conclusions on such a small body of evidence of two or three weeks working with him.
"It's a bit different if you ask me for an opinion on Odemwingie, Cox and Fortuné because I can give you an opinion over four months and quite a few matches they've played in the first team for West Brom.
"With Miller a lot of it is based on the past."