Thomas is out on loan at Leeds United and the Championship outfit are believed to be keen to extend the 29-year-old's stay at Elland Road.
Thomas has yet to feature for Albion under Steve Clarke but the club claim he was sent out to play regular football after an operation in the summer and not with a view to a sale.
"The reason Jerome went out was to get games under his belt," Downing told the Birmingham Mail.
"Steve found he couldn't give that regularity of games so we wanted him to go out and get some football.
"It's a case of go out and play as much as you can over the Christmas period and prove your fitness.
"We're not shutting the door at all on Jerome. We can't fit him in at the moment, so we want him to go out to play football and get himself fully fit.
"It was unfortunate he should get injured when Steve came in. He's a good, consummate player who works hard at his game and it'll do him well to be at Leeds."
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