The Calgary Flames will use the 13th-overall pick in tomorrow’s NHL draft to fill one of two enormous holes in their lineup. Those holes aren’t so obvious now, but they will be in a year or two when the 2011 first-rounder is ready to step in.

The first is at the centre position. Olli Jokinen and Daymond Langkow are entering the final year of their contracts. Matt Stajan has three years on his deal, but it’s unlikely they will all unfold in Calgary, unless he finds a way to re-learn the game. Mikael Backlund is a keeper, but probably best-suited as a second-line centre. UFA Brendan Morrison was versatile and useful, but he’s in the ninth inning of his career.

The top centres in the draft all have the pedigree to develop into No. 1 centres in the NHL. But Ryan Nugent-Hopkins, Jonathan Huberdeau, Sean Couturier and Ryan Strome will all be among the top six or seven picks. Then there’s Mika Zibanejad, Zack Phillips, Alexander Khoklachev and Mark McNeill. They’re centres who will be among the top-20 picks. But it would be a stretch to say they’re future No. 1 centres.

In The Hockey News mock draft, prospect guru Ryan Kennedy has the Flames selecting Phillips at No. 13. He’s a goal-scoring pivot from Saint John who racks up the numbers, but isn’t a very good skater.

Another huge hole in Calgary’s future lineup was created when 2009 first-rounder Tim Erixon rebuffed the organization and forced GM Jay Feaster to trade his rights or lose him. This was a huge blow. Erixon has all the tools and traits to develop into a top-pair defenceman for the Rangers.

Calgary’s best bet among blue-line prospects now is T.J. Brodie. So with Cory Sarich going into his final season, Robyn Regehr on the back nine of his career and Jay Bouwmeester stuck in stagnant neutral, only Mark Giordano looks like a top-flighter a few years down the road.

There’s always hope young stay-at-home types like Brett Carson, Adam Pardy or Brendan Mikkelson will develop into top-four defencemen, but it’s more reasonable for them to be third-pair support rearguards.

Calgary was the top-scoring team in the NHL in the second half of 2010-11, so don’t be surprised to see them pick a blue-line stud like Saskatoon’s Duncan Siemens or Saint John’s Nathan Beaulieu instead.

And that never-ending quest for a No. 1 centre will continue.