Background: The number of people on sickness absence due to common mental disorders (CMDs) is a societal, workplace and individual concern. The effectiveness of several interventions has been evaluated in reducing the length of sickness absence with inconclusive results. A promising intervention is based on problem-solving with workplace involvement, but the results are limited to occupational health services and have not been replicated in Swedish primary care. This protocol describes the design of a study aimed at assessing the feasibility (e.g, fidelity, dose delivered, dose received, and context) of work-directed interventions delivered in primary care settings with a focus on problem-solving with workplace involvement among patients on sickness absence due to CMDs. Methods: This feasibility study has two phases: development and evaluation. In the development phase, a strategic sample of coordinators, general practitioners and employer representatives will participate in focus groups. Coordinators and general practitioners are recruited through primary care, and employer representatives through social media and snowball sampling. Data is analyzed with qualitative thematic analysis and the problem-solving intervention will be developed based on the findings. In the evaluation phase, coordinators and/or general practitioners take part in a two-day training session on the problem-solving intervention and deliver the intervention to patients on sickness absence due to CMDs. The outcomes are based on Linnan and Steckler's framework, for example reach, fidelity, dose delivered, and dose received collected among patients, coordinators and/or general practitioners. Self-reported return to work and psychological symptoms are collected among patients. Discussion: Before conducting a full-scale trial of a complex intervention aimed at reducing the length of sickness absence, this study aims to evaluate the feasibility of work-directed interventions delivered in primary care settings. With such knowledge, future full-scale trials could be informed on how to determine necessary modifications in primary care.