PORT ST. LUCIE David Petersons biggest disappointment Sunday was his inability to finish the Cardinals in the first inning after recording two outs. . . With two outs and nobody on base, the Mets left-hander allowed a rally that gave the Cardinals two runs against him. . . Getting two quick outs and then letting guys on is unacceptable in my mind, Peterson said on a day the Mets won 7-5 in a Grapefruit League game at Clover Park. That is something we need to work on going forward and just attacking guys. . . SEE ALSO . . Luis Guillorme has another jaw-dropping Mets moment. Overall, he lasted four innings and allowed three earned runs on five hits and two walks with one strikeout. . Peterson, who is competing for a rotation spot, has pitched to a 4. 50 ERA in his two exhibition starts. . . There were some hard-hit balls against him and he was on and off with his command, manager Luis Rojas said. I thought the last inning was the best one, but he had the three outs via contact. But hes working on stuff. The stuff was there, but I thought location-wise is where he didnt execute at times. . The Cardinals used starting pitcher Carlos Martinez to bat ninth in the lineup, but Rojas isnt in a hurry to shed the DH, as James McCann started in that spot. Unless MLB and the MLPBA reach agreement on a universal DH before Opening Day, pitchers will bat this season in the National League. . . We have been talking about that, Rojas said. Pitchers are swinging in the cage, they are getting loose, we might start hitting them a week from now or something. . . Rojas said Jacob deGrom might be the first Mets pitcher to get a turn in the batters box. . Taijuan Walker threw three innings 59 pitches in a B game. The right-handers velocity was in the 90-92 mph range, according to a major league scout, but he was working in all his pitches and throwing them for strikes. . DeGrom is the scheduled starting pitcher on Tuesday for the Mets when they face the Astros in Port St. Lucie. The game will be televised by SNY. DeGroms previous two Grapefruit League starts were on the road and not carried by SNY.