© 2013 MLB Advanced Media, L.P. All rights reserved.

6/2/2013 6:09 P.M. ET

Injured Plouffe reports improvement in strained calf

MINNEAPOLIS -- Third baseman Trevor Plouffe, on the 15-day disabled list with a strained left calf, said his calf is feeling better and hopes to be ready to return once he's eligible on June 13.

Plouffe sustained the injury while running sprints before Wednesday's game against the Brewers on the same day he was activated from the 7-day concussion DL. Plouffe had to be placed on the 15-day DL because it was a different injury than the concussion he sustained on May 22, when he was kneed in the head by Braves second baseman Dan Uggla.

But Plouffe said he's past all the concussion symptoms and is encouraged by the way his calf is responding.

"I feel really good," Plouffe said. "It feels a lot better than I thought it would."

Plouffe explained that he first starting feeling tightness in his calf while doing cardio workouts as part of his comeback from the concussion. And then strained it while running sprints before what was supposed to be his return against the Brewers on Wednesday.

"I kinda felt it tighten up when we were doing stuff to get my heart rate up when I was on the concussion DL," Plouffe said. "I felt it tighten and we stopped right away and started taking care of it and thought we had calmed it down a little bit. And then in my third sprint out there I felt it."

Considering he hasn't played since May 22, Plouffe is expected to go on a rehab assignment, but is hoping to be able to return the first day he's eligible.

"I haven't heard yet, but I assume I will be," Plouffe said. "I hope to get everything in with the treatment and the rehab assignment within the 15 days. I'm thinking I'll be able to."

Gardenhire plans to stick with eight-man bullpen

MINNEAPOLIS -- Twins manager Ron Gardenhire said he plans on sticking with an eight-man bullpen for the foreseeable future because the club's starting pitchers aren't going deep enough into games.

Gardenhire prefers to have seven relievers so he can have five position players on the bench, but said he has to keep it this way for now.

"I haven't even thought about it," Gardenhire said. "It's just the way it is right now until the starters start going deeper into games on a consistent basis. It is what it is."

Despite a heavy workload, Twins relievers have fared well with a combined 2.92 ERA that ranks fourth in the Majors, entering Sunday's game against the Mariners. But they've also thrown 194 1/3 innings, which is the fifth-most in the Majors.

"If we're going to have success, we need our starters to go into the second half of games," Gardenhire said. "We're just in June and our bullpen has thrown too many innings. It won't last -- they won't be lights out if we continue to pound them with innings. So we really need our starters to get going here and our starters know that."

Morneau continues to sit with the flu

MINNEAPOLIS -- Justin Morneau missed his second consecutive start due to illness on Sunday against the Mariners.

The first baseman, who missed Saturday's 5-4 thriller with Seattle at Target Field due to the flu, is still suffering symptoms and did not start the series finale. Manager Ron Gardenhire did say he might be available later in the game if he is feeling better.

"Basically he left me a text saying, 'If I play today at all it'd have to be DH,'" Gardenhire said. "So he's still feeling it pretty good, stomach the whole package. I told him that's not good, we don't want to mess with that … He's here and we'll see about availability as the game goes on."

Joe Mauer filled in for Morneau at first -- his first stint at the corner since April 27th's 7-2 victory over Texas. It was also just his second start at first this year.

Twins option Colabello to Triple-A Rochester

MINNEAPOLIS -- Chris Colabello was optioned to Triple-A Rochester after Sunday's 10-0 win over the Mariners.

The Twins will make a corresponding roster move before Tuesday's game in Kansas City against the Royals.

Colabello is 2-for-15 this year in six games with starts at first base, right field and designated hitter. The 29-year-old hit .358 with 12 homers and 39 RBIs in 46 games with Triple-A Rochester before being called up for the first time on May 22.

Colabello was optioned to Rochester on Wednesday, but was called right back up on Thursday, when Trevor Plouffe was placed on the 15-day disabled list with a left hamstring strain.

Outfielder Oswaldo Arcia is a candidate to be recalled from Rochester, but is nursing a sore shoulder that has limited him to designated hitter duty this week. Outfielder Wilkin Ramirez, who is on the 7-day concussion DL, is not expected to be activated on Tuesday, as he's still feeling symptoms and isn't accompanying the Twins on their six-game road trip to Kansas City and Washington.

Rhett Bollinger is a reporter for MLB.com. Read his blog, Bollinger Beat, and follow him on Twitter @RhettBollinger. Kelly Erickson is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.