I suspect we may see the Red Sox pinch running early in the games and using 2 catchers in many of the games. If that is what they are doing, having the 3rd catcher available makes a lot of sense.

This was sold in the Globe as giving them the ability to use Ellisbury in games as a pinch-hitter/runner. Although using Mirabelli or Cash as pinch hitters scares me.

If Varitek suffered a "big injury," couldn't the Sox replace him on the roster? Not for that game, but for the rest of the series/playoffs. That doesn't seem like an adequate reason to carry a third catcher.

As for pinch running, I can see a scenario that makes sense. Pinch run Ellsbury for 'Tek in, say, the 6th inning, put in Mirabelli to catch, then you have the option of pinch hitting for him the next time around.

Still seems a bit farfetched. To me, it's more likely that they'll need an extra long reliever (or even another middle infielder) than a third catcher.

I also don't know how baseball's arcane roster rules factor into this -- especially regarding players not on the 25-man on August 31. I've seen contradictory comments on the subject.

You shouldn't complain about Mirabelli or Cash unless you compare them to who they're keeping off the roster in their place and whether that player would see any action in the 5 game series.

This is what I've gathered from my readings. Of course, its possible I've mis-interpreted the roster rules.

I think part of the reason was construction of the roster of Aug 31. At that point, the Sox had the 25 active players plus 3 guys on the DL - Mirabelli, Clement, and Donnelly. That gave the Sox 28 guys to choose from.

Since Clement and Donnelly are still disabled, the Sox had 2 "K-Rod" exceptions, which they used to get Ellsbury and Lester on the roster. That left 26 players for 23 slots. The three eligible guys left off the roster were Wakefield, Kyle Snydey, and Julian Tavarez - the choice basically came down to 11 pitchers or 2 catchers.

I don't know whether or not the reason given to the Globe was the truth or spin. It could've been code for "we screwed up not putting Manny on the DL on 8/31 to get an extra player eligible for the playoffs" (ie, bring up Ellsbury before 9/1 and use the K-Rod exception for somebody else).

Basura: I don't have a big complaint about the move -- the 3rd catcher and the 11th reliever are equally unlikely to even play, let alone make a difference. But if I'd been making the choice, I would have gone with one of the long relievers -- Snyder or Tavarez. Probably Tavarez. If the Sox get way ahead or way behind in games, it'd be nice to have some guys who could soak up innings. As it stands, Lester's the only real long man.

Mirabelli isn't such a stiff as a batter. If they had to bring him in for Varitek late in the game, there isn't anyone on the bench likely to do much better. Mirabelli, this year and over the past three years, hits homers at about the same rate as Varitek. His slugging average after the All Star break is higher than Lugo, Varitek, Youkalis and Crisp.

According to tonight's Sox-Angels TV announcers, this year there is a rule change and injured player can be substituted for, but the injured player can't be used in next round.