Bent, who spent last season on loan at Fulham, is Villa's record signing, having arrived from Sunderland in January 2011 in a deal worth a reported £24 million.
However, the former England striker has fallen out of favour under Lambert and will spend the next month with Championship side Brighton and Hove Albion.
Although Villa have mustered just six Premier League goals this term, Lambert feels the move will benefit all parties.
He said: "Darren wanted to go out on loan about a month ago but with Christian Benteke being suspended we had to keep him here.
"It gets Darren's career going again and that's why I loaned him to Fulham last year, to try to get him going. But Darren wanted to go himself as well.
"Christian is coming back after Saturday and I think Gabby Agbonlahor and Andi Weimann will find their feet again in terms of goalscoring."
Lambert conceded that Bent does not fit in with his tactical approach.
"We just play a different way," added the manager. "Darren came to me a month ago saying he wanted the chance to play more games (and go on loan), which I agreed to do," he said.
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