I don't see it happening unless something big happens. We don't have anything that would really warrant getting a 2nd rounder in return unless there is something bigger at play. If we are sellers at the deadline (which is possible, though unlikely if you ask me) our big chips would be the Schenns and Coburn, maybe VL depending on how he is playing. I would consider trading the Schenns or Coburn as a big move, and there would likely (hopefully) be more than just a 2nd rounder coming back. If VL is playing well and we either have no need for him because someone has stepped up, or we are selling, he could return a second rounder. Grossmann won't get that return unless a team is desperate and he has zero health issues this season.
In a normal year a cusp playoff team who want to get in or a team who are getting ready for a run would give a 2nd for Grossmann at the deadline.
In the last 3 years:
Quincey for a 1st and a minor leaguer.
Gaustad and a 4th for a 1st.
Reghr for 2 2nd round picks.
Roy for a 2nd + prospect.
Oduya for a 2nd and a 3rd.
Clowe for a 2nd, 3rd and conditional 2nd.
Murray for a 2nd and and a conditional 2nd.
Vermette for a 2nd, a backup and a 5th.
Grossmann for a 2nd and a 3rd.
Kubina for a 2nd, 4th and minor leaguer.
Leopold for a 2nd and a conditional 4th.
Kostitsyn for a 2nd and a conditional 5th.
Gill and a 5th for a 2nd and two minor leaguers.
Moore and a 7th for a 2nd.
Goc for a 3rd and a 5th.
Meszaros for a 3rd and conditional pick.
Stempniak for a 3rd.
Torres for a 3rd.
Wolski for a 3rd and a minor leaguer.
Handzus for a 4th.
Robidas for a 4th.
Smithson for a 4th.