The thing about this whole Rendon deal is... well the thing about this whole Rendon deal is that he's yet to prove himself in the minors, so really this is all moot until he does... but the other thing about this whole Rendon deal is that fans are trying to decide where he might end up late in 2013 and into 2014 using 2012 stats as a guideline. It's not their fault. What can you do but use the most recent stats available? But it's terribly flawed because what matters most in terms of where the "hypothetical reaching his potential" Rendon will end up playing is the stats between now and whenever he's called up. What matters most is something we don't know.
This is important because if you look at 2012 of course 2nd base is going to be where you stick Rendon. Danny Espinosa had an off-year with the bat and was probably the least valuable member of the infield. Plus he's nursing a shoulder injury. Seems pretty well set, right? But there are good enough reasons why Rendon could end up replacing any of the other infielders that we really shouldn't be sticking him at the keystone just yet.
Why Ian Desmond?
We all like to assume Ian Desmond had a break-out year and will continue to hit as he has. Hell, I'm predicting some regression, and still think he'll easily be a Top 10 shortstop. But what if it's far more a fluke than a breakout?
In 2010 and 2011 he did not hit well ( roughly a .260 / .303 / .375 hitter) and he didn't field well. While I'd be shocked if he went back to being a 10 HR type of guy, I was shocked he became a 25+ guy. Shocks do happen. Fielding tends to be on the fluky side when looking at one year so perhaps 2013 was overly positive for him.
Like I said yesterday at the end of 2011 people were looking to move Ian so Rendon could get into the lineup. The 2012 Desmond is irreplaceable but if the 2011 Desmond returns we'll see the same arguments return with him.
Why Ryan Zimmerman?
Ryan's contract is too big and too long to just out and out replace him with Rendon. Plus whenever he's been healthy enough to play there's year after year saying he can hit and he can field. This isn't going to be a talent thing. He might get pushed across the diamond but he won't necessarily be replaced because the numbers he puts up and the numbers he puts into his bank account say otherwise.
Still there are numbers that might cause Ryan to be replaced by Rendon. They are 17, 61, 20, and 56. Those are the number of games Ryan has missed in the past 5 seasons (he also missed 5 one year for you completists). Ryan has had significant injuries before. He could again and if so, it would make too much sense not to slot in the natural 3rd baseman waiting in the wings.
Why Adam LaRoche?
The Nats have the least amount of attachment to Mr. LaRoche. They pretty much told him to find a better (longer) deal elsewhere and only took him back under their terms. Those terms were "We're signing you to a short term deal so don't expect to retire here" There would be a little hesitation about sitting Adam for Anthony, but given that it would only amount to doing it for a year, I think the Nats would swallow that cash if Rendon was forcing the issue, They'd end up either dealing Adam or making him a highly paid platoon-esque first baseman.
Of course you don't replace 2012 LaRoche with Rendon unless he's some sort of wunderkind. But 2010 LaRoche was pretty mediocre. Adam is going to be 33 next year. He doesn't have the best profile for gracefully aging. He could simply put up a very average, a very replaceable year. And what if he gets injured again? We've all see what that did to him in 2011.
I'm not saying I think any of this will happen. Off the top of my head I like Ian to keep playing well (with the average dropping a bit - but not markedly so). I like Zimmerman to be healthy enough to play 140+ games and do what he does. I like LaRoche to age slowly enough that he can put at least one more good year, if not two. I also like Danny to hit a little better as well.
But any of this could happen. There's not a single player here that has played very well over each of the past 2-3 years missing little if any time. There is no one you should immediately say "Well Rendon isn't going to replace that guy". Thus talk about where Rendon should play should really be shelved until he's ready to come up. He should try out ALL the infield positions and if/when he's ready, be ready for whatever the year throws at him, whether that's being thrust into a starting role, or playing super-sub for the stretch run.