The Rockies' fourth and fifth rotation spots are open, although Jason Hirsh is returning from injury last season to try to reclaim No. 4 and talented young lefty Franklin Morales is getting every shot at No. 5.
But Towers is not the only one doing well in making a challenge. Following Towers on Sunday, left-hander Mark Redman pitched three perfect innings and recorded four strikeouts. Redman is on a little better financial footing, as he is guaranteed a $1 million salary.
"Everybody's coming out of the blocks pretty clean," manager Clint Hurdle said. "Towers and Redman today were very efficient -- 36 pitches [for Towers], 34 pitches [for Redman]. Strikeouts, groundballs, good location, downhill plane ... very crisp."
Towers mixed his pitches well and felt good enough about his changeup that he didn't use the split-finger pitch he is working on. Redman had pinpoint location on either side of the plate, and went high and low effectively.
Rejecting the fallback plan: Catcher Chris Iannetta, coming off a rough rookie year in 2007, doubled twice and threw out the Athletics' Carlos Gonzalez on a steal attempt on Sunday. The Rockies have signed Yorvit Torrealba for the next two years, but Iannetta has a chance to earn increased playing time as the season progresses.
But the Rockies also have the right to send Iannetta to Triple-A for everyday playing time, especially if the ills that led to his .218 average last year reappear. It hasn't happened yet in camp, and Iannetta dismisses any notion that regular time in the Minors would be better for him than backup duty to start the Major League season.
"I don't know how Triple-A at-bats are going to translate into big league at-bats, personally," Iannetta said. "I think that's pretty dumb. I'm just trying to make the team. I gained a lot of experience last year. Obviously, if I had played better, I would have challenged for more playing time."
Iannetta entered last year touted as a Rookie of the Year candidate, and his expectations of success haven't changed. Iannetta is at the stage Torrealba endured several years ago, supporting the starter but pushing to become No. 1.
"Personally, I don't want to be the backup. I don't want that mentality," he said. "I'm not playing this game to be second-best in any way, shape or form. Settling for being the second guy doesn't make any sense, although I'd take any role I can get at the big league level."
The project: Left-hander Jeff Francis, who took the decision in a 2-1 loss to the Mexican national team on Sunday at Hi Corbett Field in Tucson, Ariz., worked on pitching inside to right-handed hitters.
"I'd give it a 5, 6, out of 10," Francis said when asked how he'd rate his effort. "I tried to go in there and missed a couple times."
The only real damage came on a triple by a left-handed hitter, Ivan Terrazas. Francis wanted that one inside, but it stayed over the plate.
Rebound time: Right-handed reliever Luis Vizcaino struggled in his first spring appearance, against the White Sox, but he had an efficient ninth against the Mexican team on Sunday. He threw a perfect inning and broke one hitter's bat on two separate pitches.
In need of a rebound is righty Matt Herges, who gave up two runs on five hits -- including a triple and a double in the ninth -- in 1 1/3 innings and took the loss against the Athletics. Herges has given up seven hits and three runs in 2 1/3 innings this spring.
Up next: Right-hander Aaron Cook, one of the rotation stalwarts, and righty Kip Wells, who is fighting for a spot, will pitch for the Rockies against the Diamondbacks at Tucson Electric Park on Monday afternoon.
Shortstop Troy Tulowitzki will get the day off from the starting lineup, with Jonathan Herrera taking his place. Marcus Giles will bat second, Tulowitzki's normal spot, and play second base. Ian Stewart will play third base instead of regular Garrett Atkins.