CLEARWATER, Fla. — The Phillies began spring training in earnest this week with their first full-squad workouts, standing five weeks from their final exhibition game before the season begins. They will use these five weeks under the Florida sun to determine their starting rotation, unravel the mystery of how their bullpen will be constructed, and finalize the alignment of their infield.

But perhaps the most important information gleaned over five weeks in Clearwater will be whether Andrew McCutchen will be ready in time for opening day.

McCutchen, the 2013 National League MVP and a five-time All-Star with the Pittsburgh Pirates, sparked the Phillies lineup for nine weeks last season before he required knee surgery in June for a torn left ACL. The Phillies foundered last summer without him at the top of their lineup. And their chances to reach the postseason in 2020 become even slimmer if he’s not healthy.

“The plan for me is to be ready,” McCutchen said. “I’m doing everything I have to do to get ready. Most times, I’m getting here at 8 o’clock and leaving at 3. I’m not sitting down. I’m on the go. I’m on the go. Like right now, I’m about to leave right here, get in the pool to warm up, and just grind today. That’s what I’m going to continue to do until I’m ready.”

McCutchen was the National League’s third-best leadoff hitter before a trainer helped him off the field after he was caught in a rundown June 3 in San Diego. The Phillies were in first place and their offense — bolstered before the season with four All-Stars — was beginning to click.

With McCutchen gone, the Phillies played leadoff roulette, trying seven hitters in the top spot. None could stick and only two teams — the White Sox and Cardinals — had a lower OPS after June 3 from the leadoff spot. There were many reasons the Phillies missed the playoffs last season, but it cannot be ignored that they fell to fourth place without McCutchen.

So it was a good sign Monday that McCutchen began the five weeks of camp by taking batting practice with the other outfielders. The Phillies, manager Joe Girardi said, will take it slow this spring with him. McCutchen will likely see limited Grapefruit League action as the team keeps its eye on opening day.

“Some days, I come in and I’m like, ‘I feel great.’ Some days, I come in and I’m like, ‘Oh, I feel OK.’ That’s been the biggest challenge,” he said. “There hasn’t been any consistency where I come in and say, ‘I feel great. I feel great. I feel great.’ But that’s supposed to happen right now. But we’re grinding through.”

McCutchen’s injury is the same that he suffered on his other knee as a teenager. But the recovery, he said, is quite different. Then the leading receiver for Fort Meade (Fla.) High’s football team, McCutchen tore his right ACL in November 2002 and missed the state playoffs. He never played football again, and missed his sophomore baseball season but recovered in time for his junior and senior seasons before being drafted.

The rehab process this spring, McCutchen said, is much faster than it was when he was in high school. He said he is already without limitations, just eight months after surgery. But McCutchen also concedes that he is 33 years old, double the age he was when his football career ended. He was asked Monday, before the first workout of a crucial five weeks, if he felt nervous about how his body would recover and if he was hopeful his knee would respond the way it did nearly two decades ago.

“There's no 'hope' in my mind. There’s a ‘know.’ I know what I can do,” McCutchen said. “I know what I'm going to do, and I know what I am doing. That's the end of it. That's why I'm going out. I'm not just running just to try and run. I'm running because I know I can run, and I'm going to run as hard as I can. As much as my body lets me, that's what I'm going to do as much as I can. I'm healed. They did the surgery.”

With that, McCutchen left the Phillies clubhouse and started his day. McCutchen is not where he was a year ago, Girardi said, but he’s improving every day. The Phillies will evaluate the outfielder every few days, determining how much of a workload he can handle. Girardi said the team will “go week by week.” And in five weeks, the Phillies hope, he’ll be ready.

“I know I’ll be ready because I’ve gone through it before,” McCutchen said. “It helped me a lot, and it’s helping me right now. When it comes to jumping, cutting, all that stuff, I go do it. There’s no timidness. It’s just doing it and then seeing where I’m at.”