Hendriks gave up four runs and nine hits in 5 1/3 innings of the Twins' 6-2 loss to the Tampa Bay Rays on Tuesday.
After a strong spring training, he was added to the rotation because Scott Baker was sidelined with elbow tendinitis and Jason Marquis took off two weeks to be with his daughter, who was injured in a bicycle accident.
Hendriks will start Sunday against Baltimore.
"I'm definitely feeling ready," Hendriks said. "I've had a good spring, and am looking to put that into the season and move forward."
Twins manager Ron Gardenhire and general manager Terry Ryan have both said they would hesitate to remove Hendriks from the rotation if he makes the most of his opportunity.
"That'd be really good," Gardenhire said. "That makes a tough decision on what we have to do after that. We hope he does really, really well. We hope we have to make a very tough decision on what to do with him right away. I'll take my chances with that."
Also happy to be through with spring training is AL Rookie of the Year winner Jeremy Hellickson, who had a 9.00 ERA and gave up six home runs in 20 innings in the exhibition season.
He gave up two runs on six hits through four innings Tuesday, and was feeling more confident after a stronger showing.
"I feel a little better every start, and I feel like I'm ready for Sunday," said Hellickson, who allowed 10 runs in a visit to the Twins on March 24. "I think I was throwing pitches that I normally would, not working on a lot of stuff."
Hendriks has been working this spring on making an impression.
After accumulating an 0-2 record and 6.17 ERA following a September callup last season, Hendriks came into this spring eager to show he could compete. He succeeded, finishing with a 2.84 ERA with 17 strikeouts and six walks through 25 1/3 innings.
"I still definitely felt like I had a lot to prove," Hendriks said. "I didn't have the best of Septembers, and I wanted to prove that I could pitch better at the major league level, and so far this spring training, I've felt I've done that. Now the real test comes in the season."
Also vying for a spot as a regular on his team is Reid Brignac, who made his latest case for becoming the Rays' shortstop Tuesday, going 2 for 2 with an RBI double.
Brignac raised his average for the spring to .333 after a miserable .193 last year. He has been competing with Sean Rodriguez for the starting spot in the Rays' infield.
Rays closer Kyle Farnsworth was scheduled to play Tuesday, but was scratched due to soreness in his right elbow and did not make the trip. . The Rays reassigned outfielder Jeff Salazar to Triple-A Durham and called up outfielder Stephen Vogt. . Twins second baseman Alexi Casilla is expected to start Wednesday's spring training closer against Class-A Fort Myers after missing the last week with an inflamed bursa sac in his knee. . Rays outfielder Sam Fuld on had wrist surgery. He's expected to miss four to five months.