Smith, 28, will face Leeds on Saturday afternoon as he lines up for Queens Park Rangers, three years after the club hastily decided to sell the target man despite an impressive 2013-14 campaign at Elland Road.
During his time in Yorkshire, Smith scored 14 goals and added seven assists in 48 games but was offloaded to Fulham on deadline day of the 2014 summer window, just a year after joining from League One outfit Oldham Athletic.
BBC Radio Leeds presenter Adam Pope stated on Twitter that he believed it "was a mistake" to sell Smith, with Deane replying to Pope by tweeting "it's called not having a clue".
Smith has since played for Fulham, where he struggled to make an impact with just nine goals in 54 games. However, a loan spell at Bristol City saw him rediscover his shooting boots with 13 goals in 20 outings.
It earned him a move to Loftus Road in January 2017, where he has remained since under manager Ian Holloway, scoring five goals in 16 league games this season.
His aerial duels with Pontus Jansson and Liam Cooper will be a determining factor on the outcome Saturday's clash, with Leeds looking to build on impressive wins against Barnsley and Middlesbrough, as well as stopping in-form Aston Villa.