JUPITER, Fla. -- Barring a trade, the Cardinals' roster of position players is set. St. Louis optioned Cody McKay to Triple-A Memphis on Tuesday, making semi-official what had already been fairly clear: Abraham Nunez and Hector Luna will both make the Opening Day roster.

Nunez still needs to be added to the 40-man roster, since he signed a minor league contract with an invitation to Spring Training. Luna, on the other hand, is already on the roster. St. Louis actually still has 15 position players in camp, but Rick Ankiel will not make the club. An attempt to pass him through waivers is believed to be imminent, if it has not already begun.

The St. Louis bench includes catcher Einar Diaz, outfielders So Taguchi and Roger Cedeno, infielder/outfielder John Mabry and the two middle infielders whose spots were secured on Tuesday. Nunez in particular caught the Cards' eye from the beginning of spring, thanks to his defensive ability and willingness to accept any role given to him.

"He's literally ready to do whatever it takes," said manager Tony La Russa. "And that's a very important part of that job -- not only keeping yourself ready, but being able to help other guys.

"[First base coach] Dave McKay had heard from one of their coaches -- and we know the coach, respect him -- that one of his favorite players on the Pirates team was Abraham Nunez. Just because of the way he carried himself. He's a real good teammate. We knew that part about him and could evaluate his ability."

Nunez likely will serve as the primary backup at shortstop, as well as a left-handed pinch-hitter. It's similar to the job he held for several years with Pittsburgh. Nunez helped his cause by playing well from the start of camp.

"I'm ready to play, ready to fill my role," he said. "I'll go out there and try to get it going and do the things they ask me to do.

"When you come to fight for a position, you've got to come ready to show them that you're ready to play. You can't come down here and expect to get ready in camp. You've got to come ready to play on the first day."

McKay saw the cut coming before it happened. He admitted to being frustrated at not having received a greater opportunity to win the backup catching job this spring.

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"I did such a good job last year with my catcher's ERA, my throw-out percentage, everything Tony asked me to do, I did," he said. "And I felt like coming in to camp here, I should have been the guy to beat out. As camp went on, I realized that I had to beat out a guy."

St. Louis still has one roster decision to make -- again, barring a trade. The Cards have three relief pitchers, Bill Pulsipher, Randy Flores and Kevin Jarvis, for the final two spots in their bullpen.

Mulder's big change: That's not a reference to the turnaround in results for the left-hander from the start of spring to his recent results. Mulder brushes off the outcome of Spring Training games, whether good or bad. One thing has caught his attention lately, though: a newly sharp changeup.

"It just came out of nowhere," Mulder said after holding the Marlins to two runs in six innings on Tuesday.

Mulder considered the changeup his weakest pitch -- a relative measure, of course -- coming in, and said it has never been this good, for this long, before.

"Maybe for one start," the southpaw said, "but it's been good this whole spring. It's helping me keep hitters off-balance. When you change speeds and throw strikes, that's the name of the game. It's not about cutting it or sinking it. It's about changing speeds. It's helped me a lot so far."

Furthermore, Mulder is utterly puzzled as to the reason for the improvement. It's as though the changeup fairy left him a present under his pillow one night this past February.

"I hold it the same way I've held it the last two years," he said. "It's just become better for some reason. No idea. But I don't care. I don't want to know why. I'm throwing it well right now, and it's all I care about."

Mulder has one more exhibition start, Sunday in Springfield, Mo., before making his regular-season Cardinals debut in the home opener on April 8 against Philadelphia.

Lincoln update: Reliever Mike Lincoln, who hasn't thrown a ball in more than three weeks, underwent a bone scan recently to try to get a better read on the condition of his mysterious elbow bone bruise. Lincoln hoped to have the scan read by a specialist within a matter of days, but as of Tuesday morning, he still didn't know anything for certain. He said that on a routine basis, he doesn't feel any pain in his surgically reconstructed elbow, but that certain actions cause him discomfort.

Like he was never gone: Reggie Sanders has come back strong after missing nearly two weeks of spring games. Sanders underwent an appendectomy on March 17; his start on Monday was his first game action since March 15. In two games back, he's homered and doubled in six at-bats. He still expects to benefit from the next five games as the season approaches, but it could be worse.

"The results are there, which is good," Sanders said, "but that's not my train of thought.

"I'll put it this way: I'm comfortable with what's going on. I'm comfortable with that. And so I'm just really working and not taking anything for granted. I'm just trying to do everything I need to do to be healthy."

For a player who thrives on seeing plenty of pitches in the spring, the missed time could have been a blow. But La Russa said Sanders' success isn't entirely unexpected.

"Guys that are veterans are able to get quality work soft-tossing and with accelerated batting practice, and he did a real good job of not wasting his time," said the manager. "He did good work with [hitting coach Hal McRae], so it's not a surprise. He's a veteran, he knows his stroke, he's not searching for answers."

Coming up: The Cardinals wrap up their Grapefruit League schedule on Wednesday with a game against the Orioles at Roger Dean Stadium at 12:05 p.m. CT. Jeff Suppan will start against Rodrigo Lopez. From there, the Redbirds head to Oklahoma City for two more games against the O's, with Chris Carpenter starting on Thursday and Jason Marquis going Friday. Both games are scheduled to start at 7:05 p.m. CT.