Tejada had a 10-game hitting streak, but his biggest contribution was on the defensive end. The folks at Baseball Info Solutions tell us Tejada had 19 balls hit to him in double play situations at second base this month.

He turned 12 of them into twin killings, a conversion rate of 63 percent. That’s a significant improvement over Castillo’s 47 percent conversion rate (the major league average for a second baseman is 52 percent).

– Mark Simon, ESPN.com.

Simon uses one stat to quantify something that’s pretty clear to every metric and eyeball in the world: Ruben Tejada is a better defender than Luis Castillo. Castillo’s certainly got experience on the 20-year-old, but Tejada appears able to mitigate his lack of familiarity with the position with his impressive range and excellent instincts.

Thus far, Tejada has not embarrassed himself with the bat, either — no small feat for a player his age in the Major Leagues. It’s still a tiny sample, but Tejada’s .269/.329/.328 line is not terribly far off the league-average .264/.333/.386 mark.

Whether Tejada can keep that up remains to be seen, though it’s not as if his Major League offensive performance is a massive improvement over his respectable Minor League history. But he appears to rely on slapping the ball to the opposite field, so it’ll be interesting to see if the league adjusts to him with a little more exposure.

If he can maintain this performance, though, he should remain starting at second base even if and when Castillo returns. Though Castillo is likely to improve upon his meager offensive line this season and be a better hitter than the rookie, Tejada’s defense makes up for the difference in production.

Castillo has not yet started a rehab assignment and is apparently recovering slowly — in that he can ever truly “recover” — from his injury, so this could be immaterial.

But if it does happen — assuming Jose Reyes’ injury is as minor as the Mets are making it out to be — how will the team handle it if Castillo returns and Tejada is still playing this well? It sets up a fascinating test for a front-office on a recent run of reasonable decision-making. Castillo will have less than $9 million owed to him over the remainder of his contract. Is that little enough for the Mets to stomach cutting him free, eating the sunk cost?

But wait! Castillo is a switch-hitter and a better offensive player and baserunner than Alex Cora. Cora is on the team because he can back up Jose Reyes at shortstop, but Tejada could just as easily slide over when Reyes needs a rest and fill that position more aptly than Cora, with Castillo replacing Tejada at second.

So if Castillo returns and Tejada still appears a better bet to be playing second base everyday, Cora should be the odd man out. But can the Mets cut Mr. Vesting Option himself, the catalyst of all clubhouse chemistry?

I’m guessing no. But they’ve been surprising me since the day Mike Jacobs got cut.