Whenever you make changes to your company's products or services, your customers are bound to have input on the changes. Make sure that you have dedicated employees whose responsibility it is to deal with customer comments and complaints. Your team leader needs to be focused on the bigger picture, which is difficult for them to do when they are bogged down in talking to customers. Have your customer service representatives make note of the comments and complaints received to be passed on to the team leader, freeing him or her up to focus on the overall progress of the project.
It is not just the others in your company who can protect your team leader, but those on the team as well. Just as a quarterback has to rely on wide receivers, running backs and tight ends to find an opening, your team leader needs to have confidence that they can rely on the members of their work team. Make sure that the people you choose to work on a team are up to the task and can handle their duties with minimal supervision. Of course, the team leader will provide general guidance, but they should not have to guide their team members through each individual step.
Team leaders report to their managers, who then report to their own managers, and so on up the chain of command in your organization. Any communications should follow the chain accordingly, meaning that those at the highest levels of the company should not be pressing your team leader for details; instead, they should seek the answers they need from the team leader's manager. This way, the team leader can focus on completing the task at hand, rather than trying to assuage the worries of stakeholders.
Of course, defenders in football can and do break through the offensive line on occasion, and this will happen to your team leader as well. However, the more protections you can put into place for your team leader, the better their chances of getting their project done on time. Listen to your team leaders to identify the areas where they could use additional support, and do your best to provide them with that support whenever it is possible.