The San Francisco Giants spent a lot of money this offseason, and early on, their investments look promising. Starting pitchers Johnny Cueto and Jeff Samardzija have been impressive in their returns to the National League, while outfielder Denard Span has been everything one could want from a leadoff hitter, in addition to being a terrific defensive upgrade in centerfield over Angel Pagan. The Giants have the pieces to compete with the Los Angeles Dodgers for the NL West crown, but in order to do so, they'll need some quality outings from the backend of the rotation too.





Jake Peavy and Matt Cain have been mediocre to begin this season. Although the pair are coming off encouraging starts recently, it would be dubious to think that both of them can continue to pitch that well going forward. In order to compete in the playoffs like so many pundits have predicted them to in this even-numbered year, the Giants will likely have to make a change in their pitching rotation. And it would be wise to remove Jake Peavy from his starting role sooner rather than later.





While Cain has been quite subpar himself, there are multiple factors which suggest he will be given a longer leash than Peavy in a starting role. Cain started his career with the organization, and has played a key role in bringing multiple World Series titles to San Francisco. He is also younger and has shown more flashes of effectiveness than Peavy up to this point. In addition to all of this, Cain has the lengthier contract, and more guaranteed money going forward. Peavy's contract, on the other hand, is up at the end of the year. And unfortunately, it seems that the explanation for his poor performance is not a mechanical issue, but simply declining skills due to age and wear and tear on his arm.





Back when he was a Cy Young award winner with the San Diego Padres, Peavy's mid-90's fastball and devastating slider baffled hitters, and earned him 3 All-Star appearances. At age 34, however, the velocity has predictably dipped. In fact, Peavy's fastball (88.6), cutter (84.8), and slider (79.4) have all dropped more than 1 mile per hour compared to last season's averages.*





In addition to his decline in velocity, Peavy also seems to have lost some of his control. He's giving up 3.38 walks per 9 innings this year, up from a much lower average of just 2.03 per 9 in 2015. This seems to be at least partially part of the game plan. Knowing his stuff is no longer as good as it once was, Peavy is opting to nibble on the edges of the strike zone more frequently rather than getting beat by throwing something down the middle. Unfortunately, hitters just aren't chasing his pitches like they used to back in the prime of his career.





One of the reasons Peavy is so hesitant to throw strikes is because of the contact hitters are making when he does come into the zone. After allowing a hard hit rate of 26.5% last season, Peavy has allowed a whopping 37.5% to begin 2016. The velocity drop, lack of command, and inability to fool hitters is the reason his ERA now sits at an abysmal 7.43.





There is evidence to suggest Peavy will not continue to be this bad, however. One number which is due for regression is his batting average on balls in play (BABIP), which currently stands at an unsustainable .372. For context, Peavy's career BABIP is actually below .300. This indicates that in addition to poor performance, Peavy has certainly been dealing with some bad luck to begin his season.





Though Jake Peavy is probably not going to continue to pitch this poorly, all signs seem to indicate that he will still be a rather mediocre pitcher even if he makes some adjustments. The 34 year old veteran is probably better suited to pitch out of the bullpen. Manager Bruce Bochy and General Manager Bobby Evans should seriously consider giving his rotation spot to younger pitcher with a higher floor, such as Chris Heston, who threw quite well in his rookie season. If Heston isn't the answer, why not call up someone with more upside from the minor league system?





The Giants have shown that they are not afraid of making the tough choice, opting to leave Barry Zito off the 2010 World Series roster, and choosing to release Casey McGehee only a few months after signing him in 2014 and replacing him with a rookie third baseman (Matt Duffy) who was not a touted prospect. If they truly hope to contend this year, replacing Jake Peavy in the starting rotation could be the tough choice that puts the Giants over the top.





*All statistics used in this article are courtesy of FanGraphs, and were accessed on May 18, 2016.