Tampa Bay had the 32nd rush defense last year, and the number 1 rush defense this year. Lavonte David has been a huge part of that, his impact on this team is what should make him DROY.
He is currently 3rd in the league in TFL with 17, behind only J.J. Watt and Von Miller. Those guys have 17.5 and 16.0 sacks respectively. Lavonte David has the most non-sacks TFLs in the NFL.
Kuechly and Wagner have put up big tackling numbers as well but I think Lavonte stands out in one key area.
Luke Kuechly...... 130 79 51
Lavonte David.... 117 94 23
Bobby Wagner.... 109 67 42
Lavonte is a little shy of Luke's total tackles number, but when you take a closer look you see David has 15 more solo tackles(which IMO are more meaninful and impressive) than assisted tackles. If they were to be weighted as they are in sacks(1.0 for solo, 0.5 for assist) Lavonte would slightly edge out Kuechly and both have better numbers than Wagner. This plus the TFLs and non-sack TFLs along with his impact on the defense itself I believe make Lavonte David deserving of DROY