The forward was shown a straight red card for a petulant kick-out at New England defender Jose Goncalves after the two wrestled over an aerial ball. Altidore disapproved of his opponent's physicality, aiming a swift boot at the centerback that did not appear to take purchase.
It was Altidore's first dismissal in MLS – he had previously only seen six yellow cards in his 51 appearances – but his second this calendar year, as he was also expelled from a U.S national team match against Switzerland in March for voicing his displeasure towards an official.
For TFC, it was their third ejection of the season, each of which has resulted in a loss.
Toronto head coach Greg Vanney was caught off guard by the reaction of his captain – Altidore was wearing the armband with Michael Bradley injured.
“I was a little surprised, it was a little bit of... an emotional response," said Vanney. "He was competing for the space, I thought he was putting in a lot of defensive work and chasing, so maybe there was some frustration there for him. And then battling for the spot, so yeah, I was a little bit surprised, because I haven't really seen that specifically from him.
“It definitely caught me by surprise.”
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Without excusing the act, Vanney sought to mitigate the forward's overreaction by saying he thought Altidore was initially fouled. Nonetheless, Altidore should have responded better.
“Getting to that second stage, Jozy lost his cool," said Vanney. "I haven't seen it, but he definitely lost his head there for a second and the call was the result.”
With the game already weighed against them, behind by one and on the road, being reduced to 10 men made any chance of a comeback less likely.
“We put ourselves up against it," said Vanney. "Prior to that we were down, we weren't necessarily playing great, we weren't taking care of the ball ... we were defending a little too passively, but that definitely was a moment where it was going to be very difficult to get ourselves back into it.”