Is Anthony Rendon worth a pickup?

For years, fantasy baseball owners old enough to have owned former Gold Glove third baseman Scott Rolen in his heyday have heard people compare Washington Nationals third baseman Ryan Zimmerman to him. Rolen was a terrific player at the plate and in the field -- when healthy, of course -- and although I suspect he's not a particularly strong candidate for the Hall of Fame, it doesn't diminish what he accomplished. Zimmerman reminds me of Rolen in that he's a very good hitter and defender at the hot corner, but it's hard to count on the guy to stay healthy. The latest reminder came over the weekend, setting into motion a scenario in which the Nationals' top hitting prospect was promoted.

Before dealing with the exciting Anthony Rendon, let's talk more about Zimmerman. Early last week he was dealing with what the team called cramping in his left hamstring, and it seemed minor. He left Wednesday's game prematurely, missed a few more and then on Saturday underwent an MRI. Later Saturday, he was placed on the 15-day disabled list, and Rendon, a masher at the plate but also with his own serious durability concerns, got the call to the majors, and he made his debut on Sunday afternoon.

While this should be a three-week injury for a strained hammy and nothing more, thus sending Rendon back to the minors, I certainly didn't like what I was seeing from Zimmerman the first few weeks defensively, and it could have been affecting his offense. Zimmerman is hitting .226 in 15 games, but watching him throw the baseball awkwardly with his new sidearm motion, it sure looked like his troublesome right shoulder was either giving him trouble or he was struggling to deal with the aftereffects.

In two of the past five seasons Zimmerman missed significant playing time (106 games in 2008, 101 games in 2011), and last year shoulder problems affected his play in the first half (.243, below-average power) until a cortisone shot somewhat famously turned things around (.319, 17 home runs). Zimmerman had offseason shoulder surgery, necessitating the new throwing motion that has turned even routine plays into adventures. Zimmerman is signed for many more years, but already there has been much discussion about him moving across the diamond to first base, making room for the prospect chosen sixth in the 2011 draft. This weekend their careers crossed paths.

Let's not panic yet and drop Zimmerman in a standard league. He was, after all, a top-50 option in ESPN average live drafts, and perhaps this really is just a minor hamstring issue, and he'll return soon. Plus, the few weeks off should help his shoulder, if he was feeling pain. The Nationals have already said Rendon will play regularly while he's in the majors, but this is no position battle. When Zimmerman is healthy, Rendon will leave. Colleague Keith Law ranked the 23-year-old as the No. 17 overall prospect back in February, praising him from an offensive standpoint. So far at Double-A Harrisburg, Rendon was hitting .292 with two home runs in 14 games, but also 14 walks versus nine strikeouts and a .462 OBP, befitting his patient approach.

Rendon made his big league debut Sunday at Citi Field in New York and went hitless in four at-bats, striking out twice against Brandon Lyon and Bobby Parnell. He flied out twice against Mets starter Dillon Gee. Rendon also committed an error. It was an inauspicious debut for a top prospect, but things will get better. Rendon can rake. Immediately my Twitter feed filled up with Rendon talk; I wouldn't call him a must-add in 10- or 12-team leagues, because it should be a short-term look in the big leagues. I wouldn't cut corner infielders Mike Moustakas, Eric Hosmer, Ike Davis, Brandon Belt, Pedro Alvarez, Will Middlebrooks or Nationals teammate Adam LaRoche, either. All those players bring a baseline of previous success, and all are among the most dropped corner infielders in standard formats. However, none is in imminent danger of being sent back to Double-A in a few weeks. When it comes to lower-ceiling corner infielders like Jeff Keppinger, Greg Dobbs, Mitch Moreland, Trevor Plouffe, sure, take the chance on Rendon. There's little to lose, and in one-year formats you can cut him and find someone else.

What if Zimmerman is hurt worse than the Nationals have led on and Rendon sticks around awhile? Well, it's certainly possible. Not all hamstring injuries are created equal. It's also possible that Zimmerman returns soon but first baseman Adam LaRoche still isn't hitting, and he's the one who gets benched (though I doubt it). The point is, yes, it is possible that Rendon hits so much in the next few weeks that the Nationals need to deal with it and just cannot send him back down. But how he hits initially will also affect fantasy owners' decision-making. I think San Diego Padres second baseman/third baseman Jedd Gyorko will take walks and hit for enough power to matter this season, like Rendon, if the team was committed to him for 500 at-bats. But Gyorko is off to a slow start and is being mass-dropped already. I don't really agree with it.

Ultimately, if you own Rendon in a dynasty league, don't overrate the next few weeks, whether he hits or not, because his future is bright. If you own Zimmerman, it's premature to cut bait, though I have modest concerns about him anyway because of the shoulder.