What is your line here?

[that_pope]

Pretty defensive there. You asked for advice, and were told the standard play in a vacuum is to threebet. If MP is totally a rock who never raises without JJ+, then a threebet isn't optimal, but that is read oriented, as is you knowing the limper will raise here.

As for your question, you have no play but to check, you said you didn't threebet so you could get a good read on the situation, so let your reading skills at it while you check.