Anthony Rendon scheduled to begin playing in minors this weekend

After 43 days on the sidelines, third baseman Anthony Rendon finally saw game action today, playing three innings and taking two at-bats in an extended spring game in Viera, Fla. Nationals manager Matt Williams indicated that Rendon will ramp it up to five innings tomorrow before heading out to a minor league rehab assignment on Friday.

This is a major step for Rendon, who has been sidelined since spraining his left MCL while making a stunning diving stop on a grounder in his third Grapefruit League game on March 9. The Nats will focus on Rendon's conditioning since the 24-year-old hasn't been able to do a lot of running with his bothersome knee injury.

"Beyond the pain, that's probably the biggest thing," said Williams. "His swing will come. The timing will come, all of that. But we don't want him getting out there too quickly and not being in baseball shape and ready to go."

In a story that will be followed closely, Williams disclosed that Rendon could work at third base as well as second during his rehab stint.

"He may play both," said Williams. "Third is a little less demanding right now, so as he gets in to the swing of it, he may get over to second base, as well. But for right now, it's gonna be third just so we can monitor it as much as possible. He doesn't have to move as much and there's no real threat of guys sliding in there on double play balls, things of that nature. So he'll start at third."

The Nationals traded right-hander Tyler Clippard this offseason to acquire infielder Yunel Escobar to be their starting second baseman. Escobar wasn't originally thrilled about the idea of moving from shortstop and needed some convincing shortly after the transaction. Escobar made a handful of starts at second during the tail end of the exhibition season before Williams moved him to third to begin the season. Escobar, who has played primarily as a shortstop during this previous eight years in the big leagues, most likely feels more comfortable on the left side of the infield.

Escobar will be back at third base against the Cardinals tonight after missing the last two games with a strained groin.

"I don't know if he'll go full out tonight," said Williams. "He will probably be a little cautious on the basepaths, I would imagine. Other than that, he's good to go."

One of the great moments of the early baseball season figures to take place at Nats Park sometime during the this three-game series with the Cardinals. St. Louis has called up 29-year-old rookie right-hander Mitch Harris. If Cardinals manager Mike Matheny calls on his new reliever, it will be the first time a graduate of the Naval Academy appears in the majors since 1921.

Harris was drafted by St. Louis in the 13th round in 2008 but was required to fulfill his military commitment, which included tours in the Middle East, before joining the Cardinals organization.

"I think it's a fantastic story," said Williams. "Serves to his country first and foremost, and worked hard to get to where he wants to be professionally, too. We approach it like we would any other guy. We hit to our strengths, but I think it's a fantastic story. And his first game being here is really interesting, as well. I think it's great. We want to beat him. We really do. But it's a great story."