With 23 pitchers currently on Toronto's 40-man roster plus another 10 non-roster invitees, Walker has to keep track of a lot of arms. And they start taking their turns throwing in Monday's intra-squad game and the Grapefruit League contests that kick off Tuesday for the Jays.
It takes a computer and more than a little know-how.
"There's a method to the madness," Walker said. "Obviously we have some priority guys we've got to ensure we get their innings in and we build it around that with a lot of the non-roster guys."
Walker starts with a target number of innings and works back from the start of the regular season to figure out how to squeeze them in.
Starting pitchers or those competing for a spot in the rotation will likely throw in the mid to upper 20s when it comes to pre-season innings. That may include a minor-league outing where the club has more control over the action.
Relievers may throw 9-10 to 13-15 spring innings with long-innings relievers likely to throw more.
Pitch count is the key variable for Walker, who is looking to gets his key pitchers work while protecting them from overuse.
"We've always have a backup plan for them. But sometimes the pitches certainly trump the innings. If they get up in that 25-30 pitch mark in one inning, chances are they're going to be pulled or they won't go back out for another inning."
There were seven pitchers designated for each side in Monday's seven-inning intra-squad game. Aaron Sanchez is slated to start Tuesday against the Pittsburgh Pirates with one to two innings planned.
Walker, a former relief pitcher himself, would hope to see Sanchez throw 90 to 100 pitches by the end of spring training.
He checks daily with pitchers and trainers to see if the numbers have to be tweaked.
"The season's a long season so obviously we're not going to jeopardize the season for an inning or two in spring training," Walker said.
At the end of the day, Walker is at his computer logging in the numbers and making sense of it all.
"I may have to use two or three pitchers that were considered backups that day that pitched. So the following day we're scrambling a little bit to make sure we're covered. So there's adjustments every day. We're adding and subtracting and checking with trainers. Maybe somebody needs an extra day, somebody is ready to go that we thought wasn't ready to go.
"So it's a daily grind. It's fun. It's definitely computer-oriented, mixing and matching."
Technology can only do so much, however. Some of the information is in Walker's head. And a notepad still helps.
"There's also a lot of times when I'm scratching things out with my pen, which is easier for me sometimes" he acknowledged.
"There's a plan in place, no doubt about it," he added. "And we do our best to stick to that plan."
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