I certainly like the on-base skills Antonelli showed at the minor league level, but to expect him to get his first real extended amount of playing time in the majors for the first time at age 27 and out-produce Andino seems... doubtful. Here is the whole list of second and third base-man to get 300 plate appearances in their first season at ages 27-28 who beat Andino's 2.0 rWAR from last season:
Ron Theobald (1971), 452 PA, 2.4 rWARThat's it - five guys. And one could argue that Iwamura shouldn't count, given his time in Japan. It's certainly possible that Andino won't repeat his 2011, but it seems more likely that he'll do so than that Antonelli is good enough to do what very few other players in baseball history have been able to.
Spider Jorgensen (1947), 506 PA, 2.4 rWAR
Coco Laboy (1969), 616 PA, 2.3 rWAR
Akinori Iwamura (2007), 559 PA, 2.2 rWAR
Eddie Stanky (1943), 616 PA, 2.2 rWAR
In his time at Triple-A, Antonelli hit .237/.347/.369. That doesn't inspire a great deal of confidence, though part of that was a low BABIP (~.275). Maybe that will carry forward, but in any case, he'll need to continue taking walks (13% rate at Triple-A) to produce enough with the bat to make up for what sounds like a below average glove. How many of those older first-year infielders posted even a 10% walk rate? Six:
Eddie Stanky (1943) - 14.9%The thing is, though, these types of player don't tend to get chances at all. There are only 23 second/third-basemen who had their first season at ages 27-28 and got any significant playing-time (because players who are good enough to start in the majors are usually good enough to show up earlier). Just getting 300+ plate appearances would be something for Antonelli - if he does, it's probably a clue that he's playing pretty well (or there have been some injuries).
Spider Jorgensen (1947) - 11.4%
Ike Rockenfield (1905) - 11.4%
Al Rubeling (1940) - 11.2%
Spook Jacobs (1954) - 10.4%
Akinori Iwamura (2007) - 10.4%
It's good that the Orioles were willing to take a chance on a potentially undervalued player. Relying on him to reach his ceiling as part of Plan A would be slightly less good. We'll see how it plays out.