These type of signings haven't generally worked out very well for the Sox recently -- Wade Willer, Joel Pineiro (sp?), Colon -- but it's worth the gamble.
I can't help but wonder, though, if the $5 million would have been more effectively spent by upping the offer made to Teixera. Maybe not, but again, I wonder. $5 million isn't exactly a pittance, although it could certainly be a bargain if Penny recovers 100%.