PHOENIX -- James Shields’ first bullpen on Wednesday went so well that he’s already scheduled for another on Friday.

The White Sox pitcher already has his eyes on the next few steps he’ll take, which potentially could include a three-inning simulated game on Monday. On the 10-day disabled list retroactive to April 21 with a lat muscle strain, Shields is very encouraged only three weeks after he was shut down. He’s one of several White Sox pitchers who have made good progress of late along with Carlos Rodon, Nate Jones, Jake Petricka and Zach Putnam.

“I can’t feel anything right now,” Shields said. “Just trying to build up arm strength as quickly as possible. Surprisingly it’s back a little bit quicker than I thought. It’s actually coming out pretty good.”

“It went really well. Threw 30 pitches. All my pitches. With some good effort.”

Shields has gone from frustrated to upbeat over the last 11 days. He began to play catch when the team started it’s 10-game road trip and hasn’t had a setback. The right-hander and the club are mapping out what Shields will do next based on how he’s responding.

“We are trying to figure that out right now,” Shields said. “I think tentatively I’m going to do almost like a three inning bullpen on Monday. That’s kind of how far I’ve gotten right now.

“Everything feels really good.”

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From a physical standpoint, Putnam’s first time off a mound was good. He just wasn’t as pleased with how he threw on Tuesday night.

Putnam, on the DL with right elbow inflammation, had thrown multiple flat-ground bullpens before he moved to the mound for the first time in a month. While he wasn’t thrilled with the first effort, he wasn’t surprised, either.

“Even if you have a completely healthy arm, you know a month off the mound and you get back up there, you will have some aches and pains,” Putnam said. “I’m not disappointed. I’m not frustrated. I’ve got to build up.

“Having this be the first time in a while, I’m not concerned about it at all.

“It’s not a linear process. There’s going to be some ups and there will be some downs. If it were just kind of every other day you go throw and you feel a little better than last time, that would be great. I would love that. But it’s not always that way. I learned that last year. I’m just trying to be cognizant of that as we go forward.”