Blackett knows Denman well, having played with the 23-year-old prop at Leeds and Rotherham and coached him at the Titans.
The pair got the chance to catch-up on Saturday as Saints hosted the Championship team in a pre-season friendly at Franklin’s Gardens.
And Blackett had nothing but praise for his close friend, who moved to Northampton last summer and went on to make 23 appearances in an impressive first season.
“Gaz has done very well there (at Saints),” said the Rotherham boss. “He’s still very young for a prop, but has the right attitude on and off the field to be successful.
“People forget how young he is. He’s got a long way to go. The one thing that stands out with Gaz is his attitude and his hunger to be successful.
“Hopefully with a bit more experience he’ll be able to push for more starts at Northampton.”
Another former Rotherham player, Sam Dickinson, has also made a big impact since switching to Saints.
And Blackett has been impressed by the meteoric rise of the powerhouse No.8, who represented England Saxons last season.
“I only sort of know of Sam as I wasn’t here when he was here, but I played against him and I know everyone here has nothing but good things to say about him,” said Blackett.
“He’s a fantastic player and it’s great to see him doing so well.”