Luke Freeman missed Millwall’s 2-1 win over Cardiff City due to a hamstring problem.
The Sheffield United attacking midfielder, who recently joined the Lions on loan, made his debut in Tuesday’s 3-0 derby reverse at Fulham.
But Freeman was absent for today’s Championship fixture at The Den.
Benik Afobe also had to be subbed off in the closing stages against Cardiff.
“He [Freeman] has felt his hamstring,” said Rowett. “He’s trained really well. played against Fulham and been really bright for a week. I was really excited to see him play, so that’s disappointing. We’ve had that scanned today – we haven’t had the results back yet.
“Benik looked like he felt his hamstring late on in the game – that’s why he came off. Oliver Burke had about two or three knocks, that’s why he came off.
“The frustration for us is that you put Jed back in – a little bit fitter – and you see the impact, certainly second half, as the game goes on that he has. We can’t afford to lose the attacking players that we’ve got. Every time we get a result we seem to have to count the cost on the back of it.
“We certainly don’t seem to have had much fortune this season with injuries to key attacking players.’