Lovie Smith in a recent press conference commented that Mason Foster will supplant Lavonte David as the man with the microphone. It's not unfamiliar territory for him, as he had the task in his rookie season, however this is a bad move for a few reasons.
First and foremost, Mason Foster will not always be on the field. David will never be given plays off absent injury- therefore making considerably more sense that he be given the responsibility of wearing the microphone. According to Football Outsiders, David participated in 252 more defensive plays than Foster in 2013, and a staggering 320 more snaps in 2012 (special teams not contributing to the total, clearly). In fairness, one can make an argument that Foster is, and can be used as, a "three down" linebacker. That argument need not be made for David, though, because he is a three down linebacker. After last season, David might be the best linebacker in the league. Since No. 54 is in that argument, this is a nice lead-in for my next point:
David is a far superior linebacker to Foster. Athleticism doesn't lend itself to scheme comprehension- understood. In David's case, his instincts and ability to read the offense carry him into the fold of elite players. He finds himself in the right place at the right time frequently because he adroitly diagnoses the offense. This is what is asked of the player responsible for calling audibles.
Lastly, David has been performing this duty for the past two years and will certainly be more comfortable doing so come August than his counterpart. While they both will have to learn a new scheme/verbiage, Foster will have to tandem this with shaking off the rust of transitioning back into the responsibility.
This isn't meant to malign Foster, nor is it implying that this change will lead to a calamity. I understand that Lovie Smith is installing a different scheme than these players have played since their arrival in Tampa- and further recognize that whoever has the responsibility must learn the scheme and terminology. It is also likely that the new defense has a greater focus on MLB play, which would be reason enough for the coaches to make this change. Notwithstanding this information, I believe it to be a mistake to transfer the duties.
I reiterate that Foster is capable. David is simply more so. Even if their intangible abilities were identical, the onus should lie with the one who will be taking more snaps.