As I thought, Seth Frankoff was just in Chicago to piggyback with Mike Montgomery on Friday:
#Cubs to recall Felix Pena, send Seth Frankoff to Iowa.— Bruce Miles (@BruceMiles2112) June 10, 2017
Felix Pena is on his third recall to the Cubs this year. In the previous two he's made four appearances, thrown eight innings and allowed three earned runs with nine strikeouts.
Pena has a good arm and if he can ever harness his command and control he could become a decent major league reliever. He's one of the final players remaining in the Cubs organization from the Jim Hendry era, as he was signed by the Cubs out of the Dominican Republic in 2009.
As for Frankoff, I don't necessarily expect him to return to the big leagues anytime soon. As I said above, he was almost certainly up just to piggyback with Mike Montgomery. He did, at least, have a sense of humor about giving up a homer to Charlie Blackmon of the Rockies: