Cruz, the Giants' Pro Bowl wide receiver, was diagnosed with a bruised heel. Baas, their starting center, suffered a sprained left MCL. X-rays were negative on both players, who will continue to undergo tests on Monday.
"[Cruz] jammed his heel and was sore," coach Tom Coughlin said after the Colts beat the Giants 20-12. "He runs to make a living and he's obviously got an issue with the heel. Hopefully it is not going to be a long thing."
Coughlin said he didn't have much more information on Cruz and Baas.
Cruz emerged from the locker room later in the first quarter out of uniform but later went back into the locker room. It was unclear how Cruz injured his foot. Eli Manning attempted a deep pass to Cruz, who had beaten two Colts defenders. But Cruz got tied up with a Colts defender going for the ball after Manning's pass was underthrown, and the Colts' Greg Toler was flagged for pass interference for a 39-yard gain for the Giants.
"He said he felt fine," wide receiver Hakeem Nicks said of Cruz. "I don't really know what the details of what the injury was, but he said he was fine."
On the same drive, Baas had his left leg rolled up on by a Colts player and had it examined on the sideline before going into the locker room. Jim Cordle replaced Baas on the first drive.
"He stood up and walked off," said Cordle, who did not know the severity of Baas' injury. "So hopefully it's not too bad."
Coughlin said Monday that Baas would be evaluated on a weekly basis.
"(Baas' injury) is a weekly thing for us," Coughlin told reporters on a conference call. "We will see exactly where (Cruz) stands with (the heel injury) as the days go by. He will probably not practice tomorrow. We will have to take that one as it comes."
Baas underwent surgery this past offseason on various body parts -- the center would not reveal what he had repaired -- and was hoping to play pain-free this season. The Giants have options at center if Baas is in jeopardy of missing the season opener on Sept. 8. They can move versatile left guard Kevin Boothe to center or they can use Cordle with the starters.
Cruz had a 57-yard touchdown catch from Manning in the Giants' preseason-opening victory over Pittsburgh last weekend and showed no signs of rust after missing most of the offseason team training due to his contract negotiations. The Giants locked up Cruz to a six-year, $45.879 million contract before training camp.
Sunday marked the first time this preseason that the Giants had both Cruz and Nicks, who sat out the preseason opener with a groin injury, on the field together in a game.
"I really don't think it is that serious," Nicks said of Cruz's injury. "I think they just played it safe by holding him out. But I don't really know too many details about it."