You said "we have no help in the minors that we could look too next season". Any of Gurriel, Urena, SRF, Alford, McGuire, Ramirez, Harris, Tellez, Greene, Pentecost can make it to the big leagues by next season or earlier.
Obv some of these players will never make it at all, but it's very unlikely that none of them will.
If by "legit impact player who can give us a big boost" you mean someone who could compete for rookie of the year, I'd put Alford and Gurriel as the most likely.