For one amazing month in 2013, it appeared the Twins had found the natural successor to Joe Mauer as their catcher. On Friday, they gave up on Josmil Pinto ever assuming that role.

Pinto, once a top prospect who batted .342 with four home runs in an impressive 2013 September call-up with the Twins, was claimed off waivers by the San Diego Padres on Friday, ending his 10-year career in the Twins' minor league system.

"It's too bad the way things played out for him. He had a really good year in Double-A [in 2013], but the last two years were a struggle, especially with injuries," said Brad Steil, Twins director of minor league operations. "It was a tough decision."

The Twins added seven players to their 40-man roster — six pitchers and slugging outfielder Adam Brett Walker — to avoid losing them in next month's Rule 5 draft. To create roster space, they tried to outright Pinto and righthanded reliever A.J. Achter to Class AAA Rochester, but both had to pass through waivers. Like Pinto, Achter was claimed, and is now property of the Philadelphia Phillies.

"You evaluate everyone, trying to find space," Steil said. "We didn't want to lose these guys, and we wish them well. But it's got to be somebody."

Pinto was never able to follow up his strong first impression, and his defensive abilities remained subpar. He hit .219 in 57 major league games in 2014, and his hopes for a bounceback season were ruined last spring, when he was hit in the head by Orioles outfielder Adam Jones' bat and suffered a concussion. Additional injuries, perhaps including another concussion — doctors couldn't pinpoint an incident that caused his symptoms to return midseason — limited Pinto to only 64 games this year at Class AAA Rochester.

A.J. Achter had a 6.75 ERA with the Twins this year.

As for Achter, he piled up 14 saves as Rochester's closer "and was a big part of that team winning as many games as it did," Steil said. But he is 27 and posted a 6.75 ERA in 13â…“ innings with the Twins.

Added to the Twins' 40-man roster Friday were pitchers Taylor Rogers, Pat Dean, Randy Rosario, J.T. Chargois, Yorman Landa and Mason Melotakis, in addition to Walker, who led the Southern League with 31 home runs last season.

One common theme to the additions: velocity. Chargois, Melotakis and Landa all reach or approach 100 miles per hour with their fastballs, and the Twins clearly feared having them plucked from their system, even though Chargois and Melotakis each required Tommy John elbow ligament replacement surgery in the past couple of seasons.

Dean and Rogers spent the entire 2015 season in the Red Wings rotation, and hope to follow Tyler Duffey's path to the majors. Rogers is a 24-year-old lefthander who posted a 3.98 ERA in 27 starts. Righthander Dean, 26, led the International League with 179 innings pitched and three shutouts, to go with his 2.82 ERA.

Landa, 21, had a 1.25 ERA in 36 relief innings with the Kernels and the Twins' Gulf Coast League team, while Rosario, 21, had a 3.06 ERA with those teams and is projected as a future starter.

Walker is considered the Twins' best minor league power prospect, having led his league in home runs in all four of his professional seasons. He batted .239 with 31 home runs and 106 RBI at Class AA Chattanooga last season, and added five more home runs in the Arizona Fall League.

More netting

The Twins believe Target Field "is already in compliance" with new guidelines for safety netting to protect fans, a policy that Major League Baseball intends to recommend next month, team President Dave St. Peter said.

MLB is still developing its guidelines, St. Peter cautioned, so the team won't know until they are finalized what changes may be necessary at the six-year-old ballpark. But "based on the discussions that we have been a part of, Target Field, which has netting extending from dugout to dugout, already meets or exceeds most of the standards that are being considered," St. Peter said.