1 month sample sizes don't mean much. Not much can be made out of a 18 IP sample size. For example, Luis Atilano had a 3.69 FIP in June in 28.2 IP. Or how about Craig Stammen's 3.62 FIP in June in 19 innings. J.D. Martin had a 3.60 FIP in May. Or Livan Hernandez who had a Strasburg-esque 2.21 FIP in July in 38 IP. I'll rely on the bigger sample size which since his return he has a 4.94 FIP. His career FIP is 4.86. He has a WHIP of 1.45 in his last 5 seasons. He is a mediocre pitcher. Funny how Lannan has always been a lucky pitcher in your eyes, but Marquis has always been the proven MLB starter despite the fact that his career FIP is lower than your whipping boy John Lannan. I'm still waiting to hear how a 4 BB 1 K or 3 BB, 1 K, 2 HR performance is good.
Marquis is continuing his pre-surgery numbers, though. Martin, Atilano, etc could have been scouted out of usefulness.