Sinclair left Manchester City last week to join Albion.
"He's a great professional and a great player, but he just needs to go and play games," said Britton.
"I just hope he doesn't score against us. You always talk about ex-players coming back to haunt you - but hopefully that won't be the case.
"Hopefully he will be really rusty and won't last too long.
"It will be good to see Scotty because he played a massive part in getting us to where we are. He scored a hat-trick at Wembley and 27 goals in the season.
"It will be nice to see him playing again because he didn't feature too much at Manchester City."
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