Believe it or not, Vincent Brown is the second-most experienced wide receiver on the Colts' roster when considering years spent in the league. Brown is entering his fifth year in the NFL, second only to Andre Johnson, who is entering his 13th season.
Now, granted, T.Y. Hilton (entering his fourth year) has Brown topped in nearly every other category, such as games played, games started, receptions, yards, and touchdowns, but either way, Vincent Brown is one of the most experienced receivers on the roster for a Colts team that is very young at the position. In his career, Brown has spent time with both the San Diego Chargers (who drafted him with their third round pick in 2011 draft and with whom he spent the 2011-2013 seasons) and the Oakland Raiders (in 2014), playing in 37 career games and catching 72 passes for 919 yard and three touchdowns, averaging 12.8 yards per reception. He missed the entire 2012 season with a broken ankle and in 2013 was the Chargers' recipient of the Ed Block Courage Award for his comeback, but in 2014 with the Raiders he managed just 12 receptions for 118 yards in seven games played.
Vincent Brown was signed by the Colts this offseason to compete for a roster spot, as in no way is he guaranteed of one. With very talented players such as Hilton, Johnson, Donte Moncrief, and Phillip Dorsett locks to make the roster, the rest of the receivers at the position are likely fighting for one or two spots. That fifth roster spot will likely be occupied by talented speedster Duron Carter, who the Colts signed from the CFL this offseason. That would leave Vincent Brown on the outside looking in - unless the team opted to keep six wideouts (keep in mind that they have two tight ends who will likely see significant action in the passing game too in Coby Fleener and Dwayne Allen, which could result in them opting to keep only five wideouts, though not by any means making it a guarantee).
If the Colts were to keep six receivers, it would likely come down to either Brown or Griff Whalen, and you'd have to think that Brown would stand a good chance. Unless the Colts would want to keep Whalen around as a possible return option (which could be a very realistic reason for keeping a sixth wideout), it would make sense for that receiver to be Brown.
Now, let's not rule out the possibility of him competing with some of the other guys for playing time, as with a very impressive training camp and preseason he might be able to not only play his way on to the roster but also on to the field some as well. But considering the abundance of weapons that Andrew Luck already has at his disposal and the limited amount of snaps and passes that will already have to be divided, the likelihood of Vincent Brown stealing significant snaps away from Hilton, Johnson, Moncrief, or Dorsett seems very slim. At the moment, he seems to quite possibly be facing a bit of an uphill battle to even make the roster, much less make it on the field.