A hybrid approach to project management combines predictive and adaptive methods, such as waterfall and agile, to suit the needs and context of the project. In this case, the project manager can use an agile approach to plan project A in sprints, which are short iterations that deliver incremental value to the customer. By starting with the module that does not require machine learning skills, the project manager can leverage the existing resources and skills of the team, while waiting for the machine learning expert to finish project B. This way, the project manager can avoid delaying project A, compromising project B, or hiring a new resource that may not fit the organizational culture or project requirements. This is consistent with the PMI-PBA practice of planning and monitoring the business analysis work and the PMP practice of executing the project with urgency. References:

PMBOK Guide, 6th edition, page 14, section 1.2.1

Agile Practice Guide, page 8, section 1.2.2

PMI-PBA Exam Content Outline, page 9, task 1.2

PMI-PBA Certification Exam Prep Guide, page 65, section 3.2.2

PMP Exam Content Outline, page 7, task 2.1

PMP Exam Prep, 10th edition, page 32, section 1.4.2