Anthony Rendon in Viera. (Jonathan Newton/The Washington Post)

BOSTON — Anthony Rendon and his left knee still have a ways to go before he returns to the Nationals, but his progress of late has been encouraging. He threw from 100 feet on Saturday while rehabbing in Viera and “didn’t have an issue,” Manager Matt Williams said. He also took dry swings with his bat and hit off the tee on Saturday — again without any issue.

“Those are very important milestones,” Williams said.

So, while the Nationals are in Boston on Monday, Rendon was expected to graduate to hitting soft toss. Rendon has been out since March 9 in spring training with a sprained medial collateral ligament. The pain hasn’t been an issue right now, but it was before when he moved laterally. It might pop up again as the activity on his knee increases but so far so good.

“The rotation stuff on his knee is good,” Williams said. “So now it’s about getting him in baseball shape, so we’ll be able to progress accordingly from that.”

There is still not a firm timetable on Rendon’s return. He still has to take full batting practice before he can play in minor league games in Viera. And then he would need to go on a minor-league rehab assignment before he rejoin the Nationals.

“I’m pleased with the process and we’re just gonna take it like we said at the beginning,” General Manager Mike Rizzo said. “It’s week to week, and we’ll just see where he’s at.”

Rendon’s return date isn’t the only question that will hover over the next few weeks. Where will he play when he returns?

Williams said Rendon is taking ground balls at both second and third base in Viera. For now, at least publicly, the Nationals aren’t prepared to say where Rendon will play once he returns and, as a result, what that will mean for Yunel Escobar, who started the spring as a shortstop converting to second base but moved to third base when Rendon’s knee injury kept him out longer than expected.

“Right now, we just want (Rendon) to do work,” Williams said. “We just wanted to make sure he’s getting some work done, some baseball work done, so we’ll make those evaluations and those decisions when we get there. Right now, there are some issues with that injury being at second base and somebody sliding into him. That could cause an issue. So that’s clearly in our mind and we’ll make those evaluations when we have to.”

“We’re gonna discuss that with the player as a staff, and we’ll come up with what’s best for Anthony personally and best for us as a team,” Rizzo added.

Williams raised one of the many factors to consider: Rendon’s knee could be more exposed to slides at second base. And, of course, second base has a lot of lateral movement and twisting, perhaps more than third. Rendon proved an adept second baseman when he played there in 2013 and the start of the 2014 season. But third base is Rendon’s natural position, and where he shined last season.

The adjustment to second base for Escobar, who spent most of eight years as a major league shortstop, hasn’t been easy but he was willing to do it after he met with the team to start spring training. He entered this season with as much major league experience at second base (21 games in 2007) as third (22 in 2007). All the angles on the other side of the diamond are reversed and that’s tricky. Escobar also missed two weeks of spring training games and time to work at second base because of an oblique strain.

“At second base, I don’t feel as comfortable right now,” Escobar said. “I didn’t practice enough at second base to be ready. … I think I’ve adjusted well so far to the angles at third base. Playing second base again will be hard.”

Escobar has said he is playing where the team needs him but it’s not an easy transition. One talent evaluator that has seen the Nationals in spring and during the season noted that Escobar has indeed looked more comfortable at third base than second, where he was still trying to iron out his angles.

At third base, Escobar stays on the same side on the infield as he was before. He has the hands and reaction time to handle the position. “The balls comes like at shortstop but it’s more about reaction time,” Escobar said.

“I think he’s played well at third,” Rizzo added. “He looked good at second base. The fact that he’s willing and able to do both is a credit to him being a good teammate. He’s been nothing but an unbelievable guy on the team and he’s played extremely well for us. He’s put together a lot of good at-bats. He’s played well defensively at third base and, during spring training, played good at second.”

If Rendon comes back and plays second base, it wouldn’t be a reflection on him, but a way to accommodate both Escobar and Rendon. And switching Escobar back and forth between positions mid-season would be asking a lot, especially if he readily admits that he would need more work there.

“For all the practice I did there, I still had more to go,” Escobar said.

For now, the Nationals have time to make their final decision but there are many factors to weigh.

In other injury news, Denard Span continues to progress well in his rehab from core muscle surgery. He is expected to play seven innings in a minor league game in Viera. He recently tried stealing a base, and hit a triple with no issues, Williams said. Those two actions are good signs, since running and explosive movements were trouble for Span before his second operation.

Once Span plays a full game, he could be ready to go on a minor-league rehab assignment.