The Giants' All Star outfielder literally got a bad break when he was hit by a pitch today. He will miss 6-8 weeks healing from a non-displaced fracture in his left forearm. The Padres open their first homestand hosting the Giants for 4 games. Pence will certainly miss those games. The Friars' first road trip to San Francisco will be in early May. It is possible Pence could be back for those games, but an eight week recovery would have him returning just before. If he needs additional rehab time due to missing spring training then there's a chance he could miss out.
Pence was probably the Giants' second best hitter in 2014 and they already lost arguably their 3rd and 4th best hitters, Pablo Sandoval and Michael Morse, to free agency. It would appear that in April the Giants' offense will be at a major disadvantage compared to their champion 2014 club.
In addition, Pence had the longest active consecutive game streak at 383 games. That will come to an end.