JUPITER, Fla. — Manager Mike Matheny was back at the St. Louis Cardinals' spring-training complex Thursday for the first time since undergoing back surgery Monday in St. Louis.

The procedure repaired a ruptured disk and removed bone fragments that were brushing against a nerve.

"I was impressed how much better I felt right away," Matheny said. "I've still got a long way to go with it, but I'm definitely better. ... Things like your back that you use all the time, you do take it for granted. It's good to feel better."

Matheny said the surgery lasted about 90 minutes.

"They went in and found the fragment that was on that nerve," Matheny said. "They flushed it out and found another fragment. Then they flushed it out and found another fragment. I think they found four all together.

"So it was something that, as much as I was going to try to put it off, it wouldn't have gotten better on its own. I had to have it taken care of."

Doctors have told Matheny not to lift anything over 5 pounds for the next eight weeks as the back heals.

"They've been trying to scare me for the last couple days about how easy I've got to take it here for the next eight weeks," he said. "That would help the chances of not having to do anything else (surgically), so I'm going to go pretty easy for a while.

"I was kind of hoping to throw a ball, but I don't know where that is in the process."

Matheny said flights and bus rides won't be a problem because he will be able to occasionally stand to prevent the back from tightening.

"Just from flying yesterday, it's already much better than what it was," Matheny said. "They've given me some instructions on how I've got to wear certain things to help the circulation. I'll try and get up every once in a while on our flights, which I can. And on the buses, it shouldn't be that bad."

Matheny said he missed being with the team.

"I felt like I bailed on them, but it was nice to watch them even though I was kind of loopy," he said. "I was able to follow it pretty close, but it's not quite the same. I would have loved to have been here, especially as we get to this point when we get our last looks on some of these guys and some decisions that are coming right down to the end."

Kelly vs. Miller

Matheny said Thursday morning that the battle being waged for the fifth-starter's job won't be decided for a while.

Close friends and roommates Joe Kelly and Shelby Miller both pitched in a 5-4 victory over Atlanta on Thursday. Kelly allowed one run on three hits in four innings; Miller permitted three runs on six hits in 2 2/3 innings.

"My tempo was a little better," said Kelly, who regularly got ahead in the count by locating his four-seamer. "I've been working on my stride, and my stride felt a lot better. I'm just trying to (make) a more direct line to the plate. That helps with my tempo.

"Other than that, it was my third time out there. I'm just trying to get better and better each time going into the season."

Matheny said there remains plenty of time for the competition to unfold, although Kelly clearly holds the advantage.

"We've still got a long way to go here," he said. "We've just got to have our eyes open to see who's going to be the best fit overall.

"Today's not necessarily the drop-dead date. We've got plenty of time. We still can get these guys innings. All of them might not be (in games). They might be in the back (fields). We can be creative in how we can get all these guys built up."

Matheny acknowledged that Kelly, who was 5-7 with a 3.53 ERA in 24 games and 16 starts last season, has a leg up on Miller because of his longer track record.

"You have a hard time really ignoring what Joe did," Matheny said. "He came in and gave us a great opportunity to win every time he started. He gave us quality starts. But we also know Shelby took advantage of the opportunities he had.

"We've just got to look and see where they are right now. We need to see a guy that's ready to go for us."

Miller's changeup showed improvement, and he slipped one past Joey Terdoslavich for a called third strike in the seventh inning.

"I felt good," Miller said. "I gave up a couple of hits on some off-speed (pitches) early on, leaving them up. I tried to do a little too much. But I got in the groove and threw really good changeups today. I haven't thrown changeups much in games, but I got to throw those and felt really good --especially throwing them for strikes."

Cards make cuts

Pitchers Michael Wacha, Victor Marte and Eduardo Sanchez were reassigned to minor-league camp after the game Thursday.

Wacha threw two scoreless innings and struck out two in his final outing Thursday, being credited with the victory. He allowed no earned runs and struck out 15 in five games and 11 2/3 innings this spring.

Wacha was the Cardinals' first-round pick in the 2012 draft (19th overall) out of Texas A&M.

Contact reporter David Wilhelm at dwilhelm@bnd.com or 239-2665.