In fact, he's yet to even look like the wily veteran who had tossed six quality starts in seven outings before that.
Santana (4-3, 3.23 ERA) will be looking for a return to his old self when the Mets and Orioles square off Tuesday night in the second game of a three-game set, after allowing 10 runs in 10 innings since the no-no.
He'll have to do so against one of baseball's biggest surprises this season. At 39-28, the Orioles sit in second place in the American League East, 2 1/2 games behind the Yankees.
Baltimore struggled against Mets knuckleballer R.A. Dickey on Monday, notching only one hit, but Dickey has dominated just about everyone he's faced this season, and the Orioles have, nonetheless, won seven of their last nine.
Righty Tommy Hunter looks to keep the Orioles hot, though he has struggled with the long ball this season, having allowed 17 in 71 innings -- seven of which have come in his last four starts.
Hunter (3-3, 5.58 ERA) earned the win in his most recent outing -- his first victory since April 24 -- but he allowed five runs on seven hits in six innings. Despite the line, Hunter said he felt he pitched well and the results weren't indicative of his stuff.
"It [stinks] to say that's the best you felt and turn around and see five runs on the board," Hunter said after the start, in which he allowed all five runs after the fourth. "But that's the way it is going to go sometimes. Just take those first four innings and take them into your next start."
Santana, who is 3-1 with a 1.30 ERA at Citi Field, picked up the win despite similar problems his last time out. He was able to locate his fastball much better than he did while allowing six runs in five innings two starts ago.
Orioles: Reimold won't return by break
Before Monday's series opener, Orioles manager Buck Showalter acknowledged that outfielder Nolan Reimold will not return to the club before the All-Star break.
As for just how much time Reimold will miss with a herniated disk, Showalter told the media, "Let me get the rest of the information."
The Orioles haven't posted 40 wins this early in the season since 2005, when they were 40-27 on June 18. With a win Tuesday, they'd earn their 40th victory more than a month earlier than last year, when they did so on July 23.
Since returning from the disabled list last week, second baseman Brian Roberts has hit safely in four of six, for a .269 average.
Mets: Tejada rehabs
Mets shortstop Ruben Tejada restarted his rehab with Class A St. Lucie on Monday night, going 1-for-5. The Mets are going to be careful with Tejada, who has been out since May 7 with a strained right quad.
"I want to make sure, first of all, that his legs are in good shape," manager Terry Collins said. "We're making some progress. But I want to make sure this guy's legs are in shape before he gets back here."
Tejada, who is hitting .305 in 27 games this season, has already suffered a pair of setbacks in his return efforts.
Right-handed reliever Ramon Ramirez, who's dealing with a strained right quad, also began his rehab stint with St. Lucie on Monday. He struggled in one inning, allowing three runs on five hits.
Each of the Mets' last three series have resulted in sweeps. They lost three to the Yankees, beat the Rays three times, and dropped three to the surging Reds this weekend.
Hitters on the current Orioles roster have struggled against Santana, batting a combined .173 with 21 strikeouts and one homer in 75 at-bats. J.J. Hardy's .231 mark against the Mets' left-hander leads the club.
Although the Orioles are just 124-153 all-time in Interleague Play, they are off to a 9-4 start against the National League this season.