SCOTTSDALE, Ariz. — Hey, Rockies, who’s on third?

Four months after being confident enough to ship Ian Stewart to the Chicago Cubs, the Rockies are trusting utilitymen Chris Nelson and Jordan Pacheco, neither of whom has ever been a regular, to man the position.

The Rockies released Casey Blake on Tuesday, ending a short experiment. The Rockies hoped that Blake, 38, would provide a veteran’s stability at third until prospect Nolan Arenado is ready for the big leagues. The Rockies sent Arenado, 20, to minor-league camp last week. That leaves Nelson and Pacheco to share third base duties.

“We like what we have seen from both of them,” general manager Dan O’Dowd said. “And this provides our lineup with some flexibility.”

O’Dowd’s optimism had better be well-founded, because the Rockies likely can’t contend if the hot corner becomes the sinkhole it was last season. Rockies third basemen hit .222, second worst in the National League for the position. Their fielding percentage was .943. Only the Mets and Pirates ranked lower.

Stewart, projected as a 20-home run threat from the sixth spot in the order, fizzled out, hitting .156 with no home runs in 122 at-bats.

Because of their young pitching staff, the Rockies are going to need reliable gloves in the infield. Nelson, a terrific athlete with good range and soft hands, should provide that, but he’s never proved he can hold his own at the plate.

“I feel really good at third, and I’m confident I can do the job there, just like I’m confident at any other position I play,” said Nelson, 26.

He hit .250 in 63 games last year when he split time between second and third base. Nelson had just four home runs in 180 big-league at-bats last season, but the Rockies are looking for more consistent at-bats, not power, from their third basemen. The Nelson/Pacheco combo likely will hit eighth in the lineup.

Pacheco, 26, has been primarily a minor- league catcher for the past three seasons after playing second base at the University of New Mexico. His skills as a third baseman are raw, but he’s athletic enough for the Rockies to believe he will be serviceable. On Monday, in a game against the Angels, he committed back-to-back errors on groundballs. Pacheco, who has been taking extra infield practice, understands he has a long way to go on defense.

“It’s the comfort level thing,” he said. “I need to get better at that and be able to relax out there, like Nelly. You can see that with him, he’s confident and comfortable.”

The Rockies do like Pacheco’s bat. In 21 September games last season, he hit .286 with two homers and 14 RBIs. This spring, he’s hitting .405 with five doubles and a homer.

Blake signed a nonguaranteed $2 million contract in January and said he believed he could still play, despite undergoing neck surgery last September to alleviate pressure on a pinched nerve. He got off to a slow start in the spring, going 0-for-11 with four strikeouts. He ended up hitting just .150 in 20 at-bats.

The Rockies considered releasing Blake in mid-March, but manager Jim Tracy wanted to give Blake another shot. Despite some improvement, the Rockies decided Nelson’s athleticism and Pacheco’s bat were more valuable than Blake’s experience. The Rockies owe Blake $491,000 in termination pay.

Still, it was not easy for Tracy to cut Blake.

“I say this from the bottom of my heart,” Tracy said. “In my 11 years (as manager), I don’t know if I have had a more difficult get-together than the one I had this morning. That’s how professional a man this guy is.

“But the message was, we have a couple of young guys that are definitely on the come, and from a versatility standpoint, it opens some doors.”

Patrick Saunders: 303-954-1720 or psaunders@denverpost.com