I really hope so, but I highly, highly doubt he'll make a positive impact. Mo surely won't, so there's an opportunity, but I think we'll see another vet PG join the team via the vet minimum.
Nearly every really short guard (5'10" and under) who has played in he NBA has been a huge defensive liability, and I expect Felder to be as well. Really short guards get their time on court because of offense. The only really short guard I can remember who wasn't a defensive liability and actually a plus was Brevin Knight (5'10") and Michael Adams early in his career was decent. Spud Webb was decent for a brief time. Muggy Bogues had a respectable year here and there.
Isaiah Thomas is a defensive sieve but quite an impactful offensive player and that is why he plays. Damon Stoudamire, Earl Boykins, Nate Robinson, and Calvin Murphy were/are all defensive sieves.
It's hard for me to imagine Felder being a plus offensive player as a rookie to make up for what's likely to be an ugly defensive season and thus, it seems highly unlikely he'll crack the regular rotation or play any meaningful minutes, maybe ever. Delly was a plus offensive and defensive player for us--it's going to be difficult to replace that.