MINNEAPOLIS -- The Twins wanted to see how well Josh Donaldson would respond to running at full speed before they felt comfortable talking about a timeline for his return from a mild right hamstring strain.

They were evidently quite encouraged by what they saw when Donaldson ran sprints and did baserunning drills on the field Saturday morning, because manager Rocco Baldelli said it's possible that Donaldson could be activated from the 10-day injured list as soon as Monday -- his first day eligible to return -- or in the days immediately following.

"It was a very good day for him," Baldelli said. "We’re all very encouraged, including our medical staff."

Donaldson hasn't played since Opening Day, when he exited the game following a double in his first at-bat of the season. Though he went on the IL as a result of the injury, Donaldson and the Twins maintained an optimistic outlook throughout the process, and the former MVP third baseman actually began the buildup process immediately with lifts and workouts.

After ramping up to hitting and treadmill work earlier in the week, Donaldson appears to have passed the most important test. He was expected to take ground balls and batting practice before heading to the alternate training site in St. Paul for a few at-bats over the weekend.

"Hopefully we continue to build and go in the direction we’re shooting for, but with the way he looked today, I think he’s in a very good place," Baldelli said.

Twins 'pretty close' to 85 percent vaccination threshold

Though one player experienced more substantial side effects from the COVID-19 vaccine, Baldelli reported that everyone in the clubhouse is feeling healthy and ready to play following the Twins' mass vaccination event for Tier 1 personnel and families on Thursday.

The team hasn't yet reached the 85 percent threshold of vaccinated personnel necessary for loosened protocols in the clubhouse, but it did get closer than its original estimates, and the Twins are hopeful that some of the players that weren't originally comfortable receiving the vaccine will come to a decision following additional thought and discussion.

"If our guys do actually make a decision and they want to get vaccinated, I think we're going to be able to figure that out and potentially bring the vaccination here and allow them to get it," Baldelli said. "I believe that's in the cards, and we're very fortunate to have some great partners that are willing and able to help us out."

No plans to fill player development openings

The Twins are shorthanded in their player development operation, due to the movement or departure of several coordinators, but they have no plans to source external candidates for those openings at this time, though they could revisit such discussions toward the end of the season, president of baseball operations Derek Falvey said.

The organization parted ways with hitting coordinator Donegal Fergus, catching coordinator Micheal Thomas and fielding coordinator Billy Boyer during Spring Training and moved Minor League field coordinator Kevin Morgan to the Major League staff following the death of bench coach Mike Bell.

"Our view is, we have a lot of internal people that can do a lot of these jobs really well," Falvey said. "Doesn't mean we won't source some outside voices as we go, but this is not the right time for that, quite frankly. It's not the right time in the cycle within baseball to have those conversations."

With the delay to the start of the Minor League season, the Twins are structuring their Minor League camp differently, where players are grouped more into affiliates than into position groups, which decreases the need for position coordinators to lead such activities.

Falvey said that assistant field coordinator Tucker Frawley is stepping into an expanded role, and many of the pitching development staff members are also broadening their responsibilities. Morgan will also continue his involvement with the Minor League programming to some extent, working with assistant general manager Jeremy Zoll as Minor League spring training begins in Florida.