Boro are currently top points clear of Hull City at the top of the table.
Despite losing to relegation candidates Bristol City on Saturday, Aitor Karanka's men currently sit two points clear of Hull City, and, perhaps more importantly, six points clear of third place Derby County. Crucially, they have also played a game less than all of their promotion rivals.
And while they appear well on course to end their seven-year spell away from the top flight, Holloway believes that the acquisition of the Scotland forward will confirm their place in the Premier League for next season.
"I'm sure Karanka is aware of not upsetting the squad too much by bringing people in, but if they signed someone like Ross McCormack, then promotion would be all-but guaranteed. He would lift that squad and could play anywhere in that frontline," the former Millwall boss told Sky Sports.
Despite Boro's impressive depth in attack, the 29-year-old has already been linked with a move to the Riverside Stadium during this window (via Gazette Live).
McCormack is the Championship's top goalscorer with 15 strikes to his name, despite playing for a Fulham side that are languishing in the bottom-half.
And with the former Leeds man likely to receive more service if he was to make the switch to Karanka's side, it would seem unlikely that any team could prevent the club dominating the division until promotion back to the Premier League was assured.