"Here's what we now know: the Cubs will carry 12 pitchers, and that includes starters Carlos Zambrano, Ryan Dempster, Ted Lilly, Rich Harden and Marshall. Piniella said five other pitchers have secured spots in the bullpen." - Carrie Muskat, cubs.com
Carrie goes on to list Gregg, Marmol, Heilman and Cotts as four of the five.
I think I know who the fifth lock is.
On March 8th, Kevin Hart allowed two walks and two hits, including a home run, in one inning against the Texas Rangers.
Since then, Kevin's pitched four and a third innings. Here's his line in that time:
4.1 IP, 0 walks, 0 hits, 8 strikeouts.
That's called "getting the job done," and that's called "winning a spot on the Opening Day roster," depending on how literal you like to be.
Let's throw this out there as my fourth evaluation of the position battles in Mesa: Kevin Hart appears to have pitched his way on to the major league roster to begin 2009.