Steve Smith is the Ravens #1 receiver. No doubt about that. He's the most experienced receiver on the team by far, he's got the most chemistry with Joe, he's still as fiery as ever, and he's the best deep threat on the team until Perriman is ready for action.
Kamar Aiken is the Ravens #2 receiver for now, but tight end Crockett Gillmore is who Joe will be turning to when Steve Smith isn't open.
Gillmore and Aiken have both been targeted 10 times by Joe Flacco this season, but Gillmore has outperformed Aiken with seven receptions for 111 yards and two touchdowns, while Aiken only has six receptions for 88 yards and one fumble.
Gillmore also has a better seasonal projection than Aiken does. Gillmore is projected to finish the season with 56 receptions for 888 yards and 16 touchdowns, while Aiken is expected to finish with 48 receptions for 704 yards and no touchdowns.
I don't expect Gillmore to catch 16 passes in 2015. I don't expect any tight end this side of Rob Gronkowski to finish with those numbers, even if Marc Trestman runs a tight end friendly offense. But I don't think that his projected numbers for receptions and receiving yards are too far off, and Gillmore could lead the team in touchdowns this year.
Aiken definitely won't reach the numbers that he's projected to have in 2015 and Breshad Perriman is the reason why. Sooner or later Perriman will take the #2 job from Aiken, which will bump Aiken even further down the list of passing options. Crockett Gillmore has no such worry, as it is unlikely that Maxx Williams will be seriously featured in the passing game this year.
When Joe Flacco needs to find a receiver not named Steve Smith, expect him to be looking for Crockett Gillmore before he looks for Kamar Aiken.