Ballard has gone out of his way over the last year plus to not put Chad Kelly in the conversation at quarterback.
He brought in Hoyer specifically so Kelly wouldn't be the backup.
he extended Brissett even though he didn't technically have to.
He shows every sign of trying to keep Brissett, even with Rivers in the fold. Which again has the effect of relegating Kelly to third string or practice squad.
Brissett was walking wounded in the last few games of the year and not playing well at all. Kelly never saw the field.
I don't think I'm going too far out on a limb here to say that there is very limited trust of Kelly by Ballard.
You might be right, I don't know.
Him being the only WR currently available is no reason for Ballard to sign him. Yes we need a WR but we are not that hard up to pass out a contract because he is the only one available. There will be more WRs who will become available between now and the start of season. We also have the draft and there is a couple pretty talented ones that will be there when the Colts pick. There is no need to panic.