SCOTTSDALE, Ariz. -- Even when not at his best, Rockies right-handed pitcher Juan Nicasio managed to impress on Monday afternoon.

Nicasio, 25, is coming back from a broken neck he suffered last year after a line drive by the Nationals' Ian Desmond struck him in the face. But Nicasio, who went 4-4 with a 4.14 ERA in 13 starts last year in his first big league experience, is startling manager Jim Tracy with his growth on the mound as much as with his comeback.

Nicasio gave up three runs on five hits, struck out four, walked one and hit one batter in five innings of the Rockies' 4-3 victory over the Angels at Salt River Fields at Talking Stick. Four of the hits came in the third inning. One of the hits was a Howie Kendrick three-run homer.

Nicasio relies on a fastball and a hard slider. The latter pitch was not sound on Monday until his final inning.

"To go out there and know that as you're going through your outing, you're still searching for the good slider, yet you're able to put some zeroes up and the only damage is a three-run homer, that's a maturity sign for me," Tracy said. "It's maybe a maturity sign that's showing up a little bit earlier than you would expect from a young guy with the number of innings that he's pitched at the Major League level, especially after what he went through last year.

Nicasio, with only 71 2/3 innings in the big leagues in the regular season, has fashioned a 2.25 ERA and nine strikeouts against two walks in 12 innings this spring, and looks to be a front-runner for a season-opening rotation spot.

After the difficult third inning, Nicasio retired all six batters he faced in the fourth and fifth, three on strikeouts. His final pitch was a low slider that Angels slugger Albert Pujols could not reach.

Nicasio said veteran catcher Ramon Hernandez spotted a delivery flaw. Once that was corrected, Nicasio sailed.

"I'm happy because Ramon said, 'Your [front] shoulder is moving too quick; stay closed and your slider will be better,' " Nicasio said. "He told me my slider and my fastball inside will get people out."

Nicasio said he is working on becoming more comfortable out of the stretch.

"Now I'm feeling better and better," Nicasio said. "It was a long time not throwing. When I throw out of the stretch, sometimes I throw my fastball I open my shoulder. I'm working hard."