This lab experiment using psychology undergraduate students as participants investigated how the timing of low effort behaviors and excuses influence the attributions, emotions, and behavioral intentions a teammate makes towards a poor performer. Whereas most research has focused on internal causes of poor performance, this study empirically examined how teammates respond when an external cause of poor performance, task difficulty, exists. The temporal nature of the effort construct was also tested to see how two different reasons for reducing effort, low motivation and helplessness, influence teammate reactions. Results revealed the importance of displaying effort, even when faced with a seemingly impossible task. Effort directly influenced attributions, emotions, and behavioral intentions with teammates reacting more favorably when poor performers displayed adequate effort rather than low effort. The timing of low effort also mattered with teammates reacting more negatively to poor performers demonstrating low motivation, who always displayed low effort, compared to helpless poor performers, who reduced effort only when the difficulty of the task was realized. Excuses reduced negative teammate reactions. Practical and theoretical implications are discussed in terms of the importance of psychological safety and prosocial behaviors to team-based work environments.