SURPRISE, Ariz. -- Right-hander Adrian Sampson admitted he “wasn’t happy” when the Rangers non-tendered him at the end of November and made him a free agent.

“I thought I did well enough last year to hold a spot on the team through the offseason,” Sampson said. “They needed the flexibility of the roster. I understand the business decision, but I was definitely not happy about it.”

He could have gone somewhere else. Instead he decided to re-sign with the Rangers on a Minor League contract and that could turn out to be a fortuitous development for a club with a fragile starting rotation.

Sampson has been the best-kept secret in camp, but that is changing after 4 1/3 scoreless innings against the Cubs' “A” lineup on Thursday.

“Really turned my head a little bit,” manager Chris Woodward said. “It’s the best I’ve seen him all spring.”

Sampson may not be in the rotation to begin the season, but his work at the end of last season and this spring could be pushing him to the forefront in the likely event the Rangers have a future need for a starter. They might find they were lucky Sampson decided to stay in the organization despite being taken off the 40-man roster.

“I could have [left], but I like the direction we are headed,” Sampson said. “I respect the guys in the clubhouse and the guys in the front office. We have a young group of guys here. I trust the decisions. Jon Daniels has [put together] World Series teams before. I think we are headed in the right direction and I just wanted to be a part of it.”

This may come down to the Rangers simply trusting all the work their organization has done in bringing Sampson back to health and rebuilding him back into a viable Major League starter.

He was a rising star in the Mariners' organization but made just one start for them in 2016 before sustaining a torn flexor tendon that required surgery at the end of June. The Rangers claimed him off waivers at the end of the season and spent all of 2017 being patient while Sampson went through the rehab process.

He was 8-4 with a 3.77 ERA in 33 games at Round Rock last year, including 4-1 with a 2.40 ERA and a 1.17 WHIP in his last 10 starts. He followed that up with a 3.57 ERA and a 1.06 WHIP in four September starts for the Rangers.

The rap against Sampson has been a lack of swing-and-miss stuff to go with his exemplary command. The solution this spring has been a much better slider, plus using his fastball up in the zone.

“With him it’s all about the way he uses his stuff,” pitching coach Julio Rangel said. “He is throwing the slider more -- that’s the biggest thing, knowing it can be a wipeout pitch. Same thing with his fastball. He has really good command. Last year he pounded the strike zone so much, sometimes it was detrimental to him. He has the ability to go to the edges more than any other pitcher.”

Now it’s all about getting a real opportunity.

“Make it a tough decision,” Sampson said. “You’ve got to make them notice you somehow and I’ve done everything I can. … I need to continue doing it. I definitely wasn’t happy about it, but I’m in a good situation right now.”