PHOENIX -- Jimmy Nelson was the Brewers’ Great Unknown at the start of camp, and he was the Great Unknown on Saturday as players packed to head north for Opening Day on Thursday afternoon at Miller Park.

Nelson is attempting to complete a comeback from a year and a half without throwing a regular-season pitch. He was the Brewers’ best starting pitcher in 2017, one strikeout away from 200 when he dove back to first base at Wrigley Field and shredded his right shoulder. There was optimism heading into 2018, when he was ahead of schedule, and frustration when the shoulder had other ideas. He raised eyebrows in January, when Nelson said his aim heading into Spring Training was to be the Brewers’ Opening Day starter. Instead, he will open a second straight season on the injured list.

• Each team's Great Unknown entering season

On Friday, Nelson received a cortisone shot in his right elbow. He will take a few days of prescribed rest, including a visit with wife Melissa at home in Houston, where she is navigating a difficult pregnancy with twins. He will then travel to Milwaukee to enjoy Opening Day, and, if the doctor approves, resume throwing then.

“It’s not a rewind. It’s a pause,” Nelson said. “We made that pretty clear from the get-go -- that I’m not having to retrace any steps or anything, which would definitely be something frustrating.”

The Brewers have not scheduled further diagnostics, such as an MRI scan, a sign they are confident that Nelson’s recent bout of elbow soreness is just that: soreness, and not a sign of serious injury. Nelson believes it could be explained by the increased spin on his offspeed stuff -- “We actually have numbers to show that,” he said -- which he developed as he cleaned up his arm path during his comeback.

“I’m optimistic about it, because I know once we nip this in the bud, I’m 100 percent,” Nelson said. “I’m good to go. Literally, the shoulder is not a thought in my head anymore. It’s good. It’s strong. We’ve stayed on top of it in terms of range of motion and making sure it doesn’t tighten up or anything like that. That’s just maintenance stuff that’s relatively easy.

“But I’m excited, because I know once we nip this elbow in the bud then my velocities are going to be back to normal, easily, and my stuff is going to be there. I’ll be good from there on out. It’s not just getting rid of it now, but putting a plan to prevent it in the future. That’s the main focus.”

If he returns to anything resembling his former form, it would be a significant boost to the Brewers, who are entering the season with three promising but unproven starters -- Freddy Peralta, Brandon Woodruff and Corbin Burnes -- set to pitch Games 2-4 against the Cardinals at Miller Park.

Another pitcher, Chase Anderson, Milwaukee’s Opening Day starter a year ago, is beginning the season in the bullpen and is essentially the sixth starter. Nelson, if healthy, is seventh on the depth chart, slated to open the year in the rotation at Triple-A San Antonio.

“He is still actually right in line to do that, yeah,” said Brewers manager Craig Counsell.

Counsell has cautioned against drawing deep conclusions from Nelson’s early-season outings, good and bad.

“What I think is unfair is to watch him pitch two innings and then make grand statements about, ‘This is going to be different,’” Counsell said. “I think that’s completely unfair, and I don’t think we should do that. We should give him 20 innings before it’s like, ‘Alright, this is what we’re going to have to deal with.’ The whole point of this is to let him build up, let him pitch, let him adjust and adapt like players do.”

How Brewers players feel about their Great Unknown was evident on March 11, when Nelson pitched competitively for the first time since the date he was injured. When he took over in relief of Jhoulys Chacin in the fifth inning of a game against the White Sox, the entire roster was on the top step of the dugout. Fans gave Nelson a standing ovation. He surrendered a home run on his second pitch, but got through the inning.

Nelson, who made it to the Majors at age 24 in 2013, will turn 30 on June 5.

“I think he’s going to be part of how we’re going to do this,” said Chacin. “I always tell him it’s good to have him back because of all the fire, all the intensity he brings to the team. That’s going to help everybody. We’re really counting on him this year. I know he knows.”