What cap are you playing at? It matters because the lineups Hernadez faced in real life probably come in at an average of $30 million is WIS money. Even at an $80 million cap, he's going to be facing much better hitters, and the higher the cap, the better the hitter.
That said, contrarian is correct in the fact that the only stats that matter are OAV#, BB/9#, K/9#, HR/9# and a few others. These are the stats that matter when selecting any pitcher. They will be used in the WIS formula for ABS against the hitters, AVG#, OBP#, SLG#, and the various hitting #s (HR/100AB# etc.).
Real life saves play no part in determining a closer on this site, just as real life wins play no part in the success of starting pitchers. That said, with your sample size of the past 4 games, it's really too small of stretch of games to tell how he's going to perform.
If you are looking to use his innings, set him as Setup A available in the 7th or later and go with no closer. In close games, he'll act as a closer if you have no one setup in the closer role.