
The U's, managed by former Magpies boss Shaun Derry, come into this weekend's match 13th in the table on the back of three straight defeats.
Thomas, however, believes Cambridge's bad form has been more a case of bad luck and missing key players, but expects them to be more dangerous than their current status.
"I've been to watch Cambridge a couple of times this season and they're a really good side," Thomas told the official Notts site. "I think their league position belies what they offer.
"They might have underachieved, but with Cambridge I think it's to do with availability of key players through suspension or injury.
"It looks like they haven't been able to put out their top individuals consistently, which is why they might have stumbled to this point.
"But we're only halfway and they're absolutely a team that can put a good run together post-Christmas and be right up there.
"There are no doubts about what they can do but, after their recent results, they might come here and look to protect and keep the game tight.
"They might also come right out of the blocks and get at us. You've got to prepare for every eventuality."
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