As the fantasy baseball preseason heats up, the impact of various signings and injuries is becoming clearer for fantasy managers. Alex Bregman's move to the Boston Red Sox significantly narrows the competition for second base, placing Vaughn Grissom and Kristian Campbell's prospects in doubt. Clayton Kershaw's return raises questions about his workload following offseason surgeries, while Spencer Horwitz's thumb surgery pushes his timeline back. Ha-Seong Kim's shoulder surgery could keep him sidelined into May, affecting the Tampa Bay Rays' infield plans. With these developments, savvy fantasy players must reassess draft strategies based on player availability and health concerns.