I'm not sure any coach has ever used a receiver with a worse 3 cone drill than Allison at slot receiver in league history
He's got
loooooong speed, though.
Despite running a 4.67 at the Combine, we also have this:
https://packerswire.usatoday.com/20...on-creates-one-of-nfls-fastest-tds-in-week-3/
That is one late peak in the acceleration curve. You can see it in this video of his 40 run at the Combine:
http://www.nfl.com/videos/nfl-combine/0ap3000000643704/2016-Combine-workout-Geronimo-Allison
He's slow out of the box, consistent with that 7.4 3-cone, but then he gets vertical and into his long stride. By the time he hits the 30 yard mark he's motoring.
If LaFleur channels some inner McCarthy, running four go routes as we would see from time to time, Allison might be his man out of the slot.
Kidding (maybe) aside, the "big slot" concept is quite different than the Welker-model waterbug slot. With the small quick guys you're looking for that separation out of the break, but you get a small target to hit. The big slot is more like the TE slot, less quick, bigger target, bigger catch radius. I don't see that 7.4 3-cone as in itself a problem. Kelce ran a 7.1, to take one example; 3/10 of a second difference is barely noticeable.
The problem is that Allison is not a TE. The lack of initial quickness is combined with Allison's lack of bulk and physicality. He runs clean routes and he has good hands to go with the 6' 3" target, but those short routes are going to be with a lack of separation and a lot of contested balls. Slot corners and safeties are not going to be reluctant to unload on that long lean frame. I would be concerned about INTs on balls popping out on the hit and the potential for injury on slants.
I have a hard time seeing Allison in the slot on a regular basis, more a matchup and situational role. The best slot receiver on this roster is Adams. That dude is
sudden and money on the short slant
. He ran out of the slot in McCarthy's offense from time to time. We'll probably see him there again. But he has other jobs to do as well.