Gee leads National League rookies with 12 wins, but the 25-year-old is 5-6 since his hot start and his ERA has risen to 4.37 going into Sunday's game against the Braves at Turner Field.
After posting a 6.49 ERA in August, Gee is 0-1 with a 5.40 ERA in three September starts. The loss came against the Braves, although he allowed just two earned runs over six innings.
"He got off to a great start. The education he's getting now is what it takes to pitch here all year with all the innings you're going to run up," manager Terry Collins said. "He'll hit a wall. ... But he's pitched very good. ... I don't see any reason that he won't go out and pitch well Sunday."
With his 12 wins, Gee's is tied for sixth all-time among Mets rookies with Ron Darling, who notched 12 in 1984. Jerry Koosman won 19 games in 1968 and Dwight Gooden had 17 victories in 1984, the last time a Mets pitcher led National League rookies in victories.
Gee was recalled from Triple-A Buffalo for that April start when Chris Young was placed on the disabled list, and he arrived at Turner Field in a too-big suit borrowed from Mike Nickeas. Worse yet, he had to make up for his missing equipment by using a pair of Josh Thole's spikes and one of Bobby Parnell's gloves.
But he allowed just five hits and a run over 5 2/3 innings, and the Mets, who had started the year 1-11, snapped a seven-game losing streak.
That wasn't his Major League debut, as he went 2-2 with a 2.18 ERA in five starts last September, but he kept his rookie status by working only 33 innings.