The pair are expected to form manager Peter Jackson's central midfield partnership following Butcher's return to the club from Notts County.
It will be the 28-year-old's third stint at the Imps and Kerr believes that the club have signed a proven performer.
"It's a good signing, there's no doubt about that," Kerr told the Lincolnshire Echo.
"I was a bit surprised that we signed him to be honest because you wouldn't have expected him to be released by Notts County. And there were also a couple of other clubs in for him.
"From what I can remember, we did well together when he came back to the club briefly a few years back."