Some players who had the career-threatening procedure have said they feel even stronger once they fully recover. Gibson isn't sure if that's the case for him, but there are several positive signs that might suggest it.
"To be honest, I guess it just feels like when I'm playing catch sometimes, it doesn't even feel like I'm throwing the ball," Gibson said. "When I'm feeling good, it feels a little bit more effortless. It could be that I'm using my legs more, I have no idea. But for some reason, it feels a little bit different. I can't really explain it, but it's different."
Ranked No. 16 among the Twins' Top 20 Prospects, Gibson is one of seven Minnesota farmhands playing in the Arizona Fall League for the Peoria Javelinas.
Before the injury, Gibson relied on the slider and changeup as his out pitches. Since returning to the mound, he's seen that his fastball has picked up a tick of velocity. It previously stayed in the low 90s.
"The average speed on my fastball is up a little bit, so I'm having to learn with that," he said. "Each pitch is a little different. I don't have to pitch differently, but I have to use them in different ways and trust my fastball more 'cause it has more life on it. It has been a learning curve to use three pitches that have been acting a little bit differently, but it could be good."
The Twins sent Gibson to the AFL to build up innings in preparation for next season. Coming back from surgery in September, the 24-year-old right-hander threw only 28 1/3 innings in the Minor Leagues. While trying to shake off the rust, he compiled a 4.13 ERA in stints with the Gulf Coast League Twins, Class Advanced A Fort Myers and Triple-A Rochester.
In his first Fall League outing, Gibson struck out eight over five shutout innings.
"I'm feeling pretty good. I was a little tired before I got out here, but I think my last start refreshed me a little bit," he said. "My arm felt really good, it's getting innings right now; as I get them, I'll work on stuff, but the innings I get now are going to determine how many I get next year."
Standing 6-foot-6, Gibson was forced to work on mechanics throughout his recovery to make sure he stayed sharp and not regress further before throwing again.
"I'm a very mechanical guy because as tall and lanky as I am, they can get off a little bit," Gibson explained. "It's more about keeping my weight back, letting my front side travel and going forward with my arm."
While he's continuing his rehab routine in Arizona, Gibson is treating his time in the AFL like he would the middle of the regular season. The Twins are hoping they can get him back to how he performed before the injury, when he recorded 217 strikeouts in his first two years as a pro.
"The treatment that I'm doing now is normal," he said. "I'm not completely done with everything, but it's treatment I'll be doing for the rest of my career."
As for the competition the Twins prospect is facing in the Fall League, Gibson's toughest task is throwing to foes he's never seen before on short notice.
"Part of the crazy thing is you don't know them at all. Three hours before the game, I'm using someone's iPad to look up their stats," Gibson said. "That's how it is. In the middle of the season, you have a scouting report and everything, but I'm going off their batting average and home runs they hit. That's the challenge -- it's making adjustments on the fly."
That sort of blind testing is something Gibson hopes will help him develop his attacking style for when he finally gets the call to the Twin Cities.
"You have to look at the swings they take early on in the at-bat and work off that," he said. "If I see a guy leaning over the plate or pulling his front shoulder, those are the things I have to be watching for. If a guy is leaning on my fastball, then I'm going to have to come back with an off-speed [pitch] to make him stay honest. It builds your technique."
A versatile outfielder, Nate Roberts takes his high-energy play to Arizona in hopes of earning a promotion from Class A to start next season. The 23-year-old didn't begin this season until late May because of an injury, so the Twins want to get him more at-bats.
Roberts batted .299 in 76 games with Beloit, but his .433 on-base percentage turned plenty of heads. He also walked 44 times and stole 27 bases. With his ability to work his way on without the benefit of a hit, Roberts could get top-of-the-lineup looks with the Twins down the road.
After spending parts of two full seasons at Double-A New Britain, Evan Bigley played 39 games with Rochester at the end of the year before being assigned to the AFL.
The right fielder batted .207 at Triple-A and hopes to get back on track in Arizona against strong competition.
A late season callup, Chris Herrmann collected one hit in 18 at-bats with the Twins. Before making his Major League debut, the 24-year-old catcher batted .276 with 10 homers and 61 RBIs with the Rock Cats.
Caleb Thielbar saw his 2012 season begin at Fort Myers and end at Rochester. Now the 25-year-old will get another chance to prove himself in the AFL.
The southpaw struck out 74 batters and walked only 21 over 77 2/3 innings, making him a fast-rising relief prospect.
A 30th-round pick in the 2008 Draft, Michael Tonkin turned in a stellar campaign, boasting a 2.08 ERA over 69 1/3 innings with Beloit and Fort Myers. He heads to the AFL, hoping to get more innings under his belt while facing stiffer competition than he's used to.
Logan Darnell was one of the mainstays in the New Britain rotation this season, starting 28 games. Although he went 11-12 with a 5.08 ERA, the lefty struck out 98 batters and walked 47 over 156 innings.
Tyler Emerick is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.