In a congested bottom half of the table, the Canaries are two places and one point above Sunderland, who occupy the final place in the relegation zone but have a game in hand.
The Canaries are the only side in the bottom six not to have changed manager this season.
"It would be almost delinquent of the football club to not be aware of potential candidates if for any reason your manager left," McNally told the Eastern Daily Press.
"If results are not good enough you have to be aware of who is out there to help. You look at the market and who might be right for Norwich City.
"If we needed to make a change - and the average tenure of a Premier League manager is about a year and a half, which puts Chris in the top six or top eight longest serving right now - then if a change was necessary it wouldn't be a case of, who are the contenders? It would be a case of reviewing what is required, where are we going and who is best placed to take the club forward."
The bottom 11 teams are separated by eight points with 12 games to go and the Canaries are three points behind 10th-placed Swansea and West Ham, in 11th, whose recent revival has taken them clear of the drop zone.
"If we believe Chris is the right man to take the club forward then we stick with that," McNally added. "It is fine margins in our sport and what you have to be sure of is a guaranteed improvement."