Despite a challenging day for the tourists, Leach's commitment impressed assistant coach Jeetan Patel, who is confident that the spinner will return fully fit and ready for action.
Leach, a left-arm spinner, bowled 16 overs in a taxing day for England as India piled on 421-7, extending their first innings lead to 175 runs.
"He banged his knee last night when he dived at fine-leg. Then he banged it again today, and it's causing him a bit of pain, to be honest," Patel, a former New Zealand spinner, explained to reporters.
"He seemed a bit sluggish in the outfield while trying to reach the ball, but he persevered, and I think he bowled really, really well."
Patel continued, "That's what Jack brings to this team. He always gives his all. It's just unfortunate that after coming so far, diving for a ball at fine-leg results in him hobbling around."
However, Patel expressed confidence in Leach's ability to bounce back. "He'll be back. He's one of the toughest guys in the team. The workload was shared, and I thought the other guys did a really good job."
Meanwhile, Joe Root and debutant Tom Hartley shouldered the responsibility of taking wickets while Leach was nursing his injury.
Throughout the day, Leach, 32, bowled six spells, including two of four overs each. He conceded only 30 runs and bowled four maiden overs.
Patel remains hopeful that Leach will take the field on day three. "I hope the injury doesn't restrict him," Patel shared. "He has another night to rest, and he's a resilient individual who will be eager to get back out there."
Patel stressed the importance of being smart in managing Leach's injury while fulfilling his role on the team. "We still have four Tests to go, and there's another innings to come in this game. We need a player like Jack."
Although Leach's knee is causing discomfort, Patel believes he will overcome it. "It's bothering him enough. By observing him in the outfield, it's clear that it's not just a minor graze. But based on his determination to continue bowling, I believe he will be back for the fourth innings."
Leach demonstrated his prowess by dismissing captain Rohit Sharma for 24 on the first day of the Test match. Prior to that, England had posted 246 runs in their first innings after choosing to bat first in the five-match series.