It's Fernando Martinez.
Some of you correctly surmised this last night, and it makes a lot of sense. The first time around, F-Mart was still struggling with concussion issues and wasn't playing at his full capacity. Now? He's at least healthy enough for Houston to see what he can do if given regular playing time.
I imagine the lineup for now will feature F-Mart in left, Barnes in center and Maxwell in right, with Maxwell sliding over to center when Bogusevic gets the occasional start. That's not an excellent defensive outfield, but it's certainly passable for now.
As for Martinez himself, he appears in a worse position to succeed based on his recent minor league numbers. Yes, his averages are still sterling, but in his last 10 games, F-Mart has been in a bit of a slump. He's only hitting .233/.267/.395 over that stretch and has a 29/8 strikeout to walk rate since the PCL All-Star Break. His average and power numbers have both fallen off, and his walk rate still isn't super strong.
Basically, there's nothing to tell us that F-Mart will be an immediate upgrade for the offense, and may even take a step back, since his walk rate is lower than J.D.'s has been. F-Mart may have shown more power potential in the minors, but until that translates to the majors, it doesn't appear this is a huge upgrade.
Still, I'm happy to see him back and getting another shot. He's still very talented and deserves a fair shake. Let's hope he gets one on this unlucky squad.