MLB Weekend Preview: Watch Phillies-Nats, Lincecum-Greinke and Pedro Alvarez

Each Friday, we like to take a look at the weekend ahead and preview which series and storylines will be worth following.

Which division rivals are facing each other? How will playoff contenders measure up against one another? What look like the best pitching matchups? Is any player chasing an achievement worth noting?

These are our suggestions for what to watch. What are you going to be following? Please post your thoughts in the comments and keep tabs throughout the weekend. 

Phillies vs. Nationals Series

The Washington Nationals still hold first place in the NL East by one-and-a-half games over the Atlanta Braves.

But if the Philadelphia Phillies pull off a sweep this weekend in D.C., they'll be within a half game of the Nats. And the Braves or New York Mets could very well have taken over first place.

Saturday's pitching matchup of Vance Worley (2-1, 1.97) versus Gio Gonzalez (2-1, 1.82) should be particularly interesting. 

This series also has the added intrigue of the battle between Nationals Park and Phillies fans who have traveled down to D.C. and taken over the Nats' home ballpark as their own. Or turning the ballpark into "Citizens Bank Park South," as The 700 Level posted last year. 

In an attempt to maintain ownership of their territory, the Nats have declared their ballpark "Natitude Park." The Philadelphia Inquirer's Matt Gelb posted a photo of this weekend's designation on Twitter. 

Will the Nats and their fans bring some Natitude against their long-time oppressors? The series ends with a national telecast on ESPN's Sunday Night Baseball. 

Tim Lincecum vs. Zack Greinke

Perhaps the best pitching matchup takes place Friday night at AT&T Park. 

Tim Lincecum's 2-2 record and 5.54 ERA don't look impressive, but that's largely due to his terrible first three starts. In his two appearances since then, Lincecum has looked more like the ace we're accustomed to seeing. Pitching 13 innings, he allowed just one earned run with seven hits and 13 strikeouts.

Zack Greinke didn't have as rough a start to his season as Lincecum, but he's been almost as good in his two most recent starts. In 12 innings, Greinke allowed three runs with 11 strikeouts. However, he did give up 15 hits. 

A series win for either the San Francisco Giants or Milwaukee Brewers would help their teams stay close in their respective division races.

White Sox vs. Tigers Series

What's happened to the Detroit Tigers?

The heavy favorite in the AL Central came out swinging to begin the season, but have fallen in a funk recently, losing nine of their last 12 games. At 12-12, they currently hold second place in their division, one-and-a-half games behind the Cleveland Indians.

Right behind them by a half game are the Chicago White Sox. But they're not exactly hot coming into this weekend, having lost their last three series. 

The White Sox typically give the Tigers trouble, making it difficult to establish a decent lead, let alone win their division. But one of the reasons Detroit won the AL Central by 15 games last season was because they were able to dominate their division rivals.

The Tigers finished 13-5 against the White Sox last year. Asserting themselves again this season would help Detroit get back on track. 

Pedro Alvarez's Home Run Surge

On Wednesday, I wrote about the Pittsburgh Pirates third baseman finally swinging the bat that he was expected to bring to PNC Park as the No. 2 overall pick in the 2008 draft. 

Pedro Alvarez has hit safely in eight of his last 10 games. In his last six games, he's batted 11-for-23 (.478) with three homers and eight RBI. During this stretch, Alvarez has raised his OPS from an abysmal .402 to an extremely impressive .912. 

Can he continue his recent hot streak through the weekend against the Cincinnati Reds?

Aaron Cook's First Start With the Red Sox

Josh Beckett is nursing a strained lat muscle in his side and won't make his scheduled start on Saturday. The injury isn't considered serious, but as ESPN Boston's Steven Krasner reports, it's bothered Beckett for a while and the team thought that was enough to warrant giving him some extra rest to avoid further injury. 

Pitching in his place for the Boston Red Sox is Aaron Cook, who was called up from Triple-A Pawtucket just in time to prevent him from opting out of his contract. 

Cook finished with a 3-10 record and 6.03 ERA last season for the Colorado Rockies, which surely makes Red Sox fans nervous. But Cook was signed for pitching depth and that's exactly what he's providing now. 

No AL East lineup is a break for any pitcher, but at least Cook might get something of a soft landing, facing the Baltimore Orioles.

If Cook pitches well enough, manager Bobby Valentine says he'll consider using a six-man rotation for the next three weeks, according to the Boston Herald's Scott Lauber. I bet the Boston fans and media wouldn't question that decision very much. Hoo boy. 

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