BRADENTON, Fla. -- In addition to the roster cuts that Pittsburgh made on Tuesday, the Pirates also moved infielder Luis Rivas to the team's 40-man roster, essentially ensuring him of being with the club on Opening Day.

"It's not a done deal," general manager Neal Huntington cautioned. "But as we sit here right now, yes, Luis has put himself in a great position to make our 25-man roster."

In order to clear room for Rivas on the 40-man roster, the Pirates designated right-hander Jonah Bayliss for assignment. To get Rivas on the team's 25-man roster, the Pirates would have to make another roster move before Monday's season opener in Atlanta.

The Pirates signed Rivas to a Minor League contract in December, hoping that the 28-year-old infielder was beginning to show the same potential that made him a top prospect in the Twins organization early in his career.

Rivas entered Spring Training competing against Josh Wilson and Ray Olmedo to earn the backup middle-infield spot. Olmedo was lost on waivers early in camp, and Rivas outperformed Wilson both at the plate and in the field during the team's Grapefruit League schedule.

"I came here to do the best I can," said Rivas, who played just four games in the Majors last season. "I just came here every day and worked hard. I see more patience in myself."

Heading into Tuesday's game against the Twins, Rivas had a .348 spring average with five doubles and three RBIs. Last year, Rivas spent almost the entire season playing for Cleveland's Triple-A Buffalo affiliate. He hit .263 in 105 games.

Rivas attributed his offensive improvements to a change in how close he stands to the plate, which he said has given him more time to see the pitch. Huntington added that Rivas' newfound success can also be credited to the infielder's more patient approach at the plate.

"It feels good," Rivas said of his reemergence as a legitimate Major League player. "I told myself I could get back in check and get back here. It's a new beginning right now."

Defensively, Rivas has played at second, short and third this month, and he has looked above average defensively throughout most of Spring Training. He has the ability to also play in the outfield if the Pirates find themselves needing an extra outfielder to fill in.

"He's leaner and more athletic than he was a year ago," Huntington said. "As a result, he's improved his ability to play shortstop. He's made every play we expected him to make this year, and he has swung the bat better than expected."

The fact that Rivas has produced so consistently at the plate, it gives the Pirates a cushion as Freddy Sanchez's status remains somewhat in limbo.

Sanchez, who is dealing with inflammation in his right shoulder, is expected to be ready to play second on Opening Day. However, if the All-Star second baseman is not ready on Monday or if he needs periodic days off early in the season as he tries to return to full health, Rivas has shown that he is a more-than-capable replacement.

"Luis is a fierce competitor," manager John Russell said. "He works hard and goes about his business. He's in great shape. He's moving very well. He plays the game the right way. I'm very pleased with how he came in to camp, and I'm very pleased with what he's done so far."

With Rivas poised to take one of the spots on the bench, that leaves the Pirates with just a few more decisions to make before the end of the week.

Huntington said that the team will take one more infielder -- likely Chris Gomez -- though that number could rise to two because of the possibility that adding someone such as Doug Mientkiewicz would give the Pirates a player who could play both the infield and outfield positions.