SEATTLE -- Twins outfielders Denard Span and Ben Revere were held out of the lineup again on Saturday against the Mariners because of injuries, but Revere could return as early as Sunday.

Span has been out since last Sunday with an injured shoulder, stemming from an awkward dive in center field. Span has been taking swings in the cages and is throwing, but still isn't quite ready to return. Monday appears a more likely target date to be back in the lineup.

"He says it's feeling better, moving in the right direction," Twins assistant general manager Rob Antony said. "He hopes to hit on the field [Saturday] and then we'll go from there."

Revere, who rolled his ankle trying to beat out a throw at first base on Wednesday, is closer to being back on the field. He was available off the bench on Saturday and there is a good chance he'll make his return to the lineup on Sunday.

"Revere feels better [Saturday]," Twins manager Ron Gardenhire said. "He still has some bruising and swelling in his ankle. He's available if I need him in the ballgame and a possibility he'll play [Sunday]."

With Span and Revere out, Darin Mastroianni started in center field and Matt Carson got the start in right. Second baseman Jamey Carroll batted leadoff for the first time this season in their absence.

Twins to assess Blackburn's future

SEATTLE -- Right-hander Nick Blackburn has continued to struggle this season, and the Twins are going to explore their options with the sinkerballer moving forward.

After giving up five runs on 11 hits over 5 1/3 innings against the Mariners on Friday, Blackburn fell to 4-9 with a 7.39 ERA in 19 starts this season. It's been a continuation of his tough second half last season, as he is 5-14 with a 7.26 ERA over his last 30 starts, dating back to July 27, 2011.

Blackburn is under contract for next season at $5.5 million. The Twins remain hopeful he can get back to his old ways, but assistant general manager Rob Antony acknowledged the Twins are in a tough spot because of his struggles.

"It's a fair question and we're going to have some discussions about it, we're going to try to figure out what the right thing is to try and get this guy back on track," Antony said. "He had some concerning statements -- 'I'm not sure what to do.'

"When big leaguers have thoughts like that, then you know their confidence is struggling. He had a rough go again [Friday] night. He gave up a lot of hits. He settled down a little bit after giving up the three runs; I thought he battled. But he's scuffling, no question about."

The Twins will talk to Blackburn in the next few days and decide what the best course of action for him for the rest of the season.

"We'll explore all options, whether it's putting him in the 'pen, whether it's sending him down, skipping him a start -- there are a lot of different things you can do," Antony said. "We're going to get together and talk about it, try and see what answers we can come up with and what we can do differently, and what he needs to do differently, how we can try and get him going again."

Berrios off to impressive start in Minors

SEATTLE -- Twins prospect J.O. Berrios, the No. 32 overall pick in this year's First-Year Player Draft, has been impressive so far in the Minors since signing on June 15.

The right-hander has posted a 0.70 ERA with 43 strikeouts and four walks in 25 2/3 innings, split between the Gulf Coast League Twins and Rookie-level Elizabethton. His latest gem came on Friday night, when he struck out 11 over five scoreless frames.

Twins assistant general manager Rob Antony saw him pitch in the GCL, and liked what he saw from the 18-year-old Puerto Rico native.

"He's the best-looking pitching prospect that we've drafted in a long time, for me," Antony said. "He pitches and has a mound presence of a college guy. He's got good stuff, really good. He was sitting at 93-94 and touching 96. He's got a good breaking ball. Throws strikes, gets ahead in the count, can put people away, he doesn't pick at the zone at all."