Who's the top option in the lineup?

VIERA, Fla. - One of the biggest questions facing the Nationals with exactly three weeks to go before opening day is who will be atop the lineup.

Denard Span most likely won't be available to return to his normal spot until May, as he's recovering from abdominal surgery. Anthony Rendon batted first for two spring games until he went down with a sprained left MCL. Michael A. Taylor, today's leadoff hitter, has been used the most in that place in the order.

"We have options," manager Matt Williams said. "Anthony is a really good on-base guy, good knowledge of the strike zone, good hitter as well, so he's an option. Michael has been hitting leadoff a lot because we want to get him at-bats because he's going to get the majority of the playing time in spring in center. So we're hitting him there to take a look at him, too. He hit there a little bit last year (in the minors), so that being said, we want him to get accustomed to that spot in case we need to do that with him. For all accounts and purposes, Jayson's (Werth) hit there - not saying he will, but there's an option, too. We'll just have to deal with who the opposing pitcher is, where we're at as far as our team goes and make that decision every day."

Werth threw again yesterday with no issues as he continues his rehab program from January shoulder surgery. Williams said he's aiming for Werth to participate in some minor league games later this week, where the Nats have the ability to control the game. That means Werth can work on his fielding without having to make any throws.

Williams said second baseman Yunel Escobar is progressing with his recovery from a strained oblique muscle. Escobar will continue with rotational exercises today.

The Nationals optioned left-hander Sammy Solis to Double-A Harrisburg this morning. Solis, a 2010 second-round pick, underwent Tommy John surgery in 2012. The Nationals feel they have options in terms of how they use Solis.

"He is versatile," Williams said. "He can do anything. He has started. He is potentially a power lefty out of the bullpen. So he can do both. The question that arises is the resilience of his arm if he in fact is a reliever, so he'll get a chance to do a little bit of that and see how that goes."

The Mets announced this morning that starting pitcher Zack Wheeler has a torn elbow ligament that will most likely require Tommy John surgery. Williams responded to the news on his National League East foes.

"We have great competition against Zack every time he pitches against us," Williams said. "He is a great pitcher and we really have to work hard to try to beat him. It's unfortunate for him and for the Mets organization if something like that has to happen because he's a very important part of their team. So I don't want Zack to get hurt. Nobody wants that."

Jordan Zimmermann makes his third start of the spring today. Williams' plan is for Zimmermann to throw four innings or around 60 pitches. Zimmermann has given up one run on three hits with four strikeouts and one walk in 4 2/3 innings so far this exhibition season.