The Philadelphia Phillies have had one of the most disappointing starting rotations in the league. That unit is likely to become even more depleted, as Jake Arrieta is anticipating season-ending surgery in the coming days.

Arrieta has been attempting to pitch through the bone spur since the All-Star break. Despite the recommendation that he would likely need surgery, he felt that he needed to remain in the rotation to give the Phillies their best chance to win.

Technically, Arrieta actually had better numbers in the second half, posting a 4.55 ERA in six starts (compared to a 4.67 ERA in the first half) while upping his K/9 to 8.1. However, he only totaled 27 2/3 innings in those six starts, barely averaging four innings per outing. In his last start against the San Francisco Giants on Aug. 11, Arrieta gave up five earned runs in just three innings.

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The 2015 National League Cy Young Award winner has seen a pretty sharp decline in form since 2016, which–not surprisingly–has coincided with a drop in velocity. Arrieta average fastball velocity was 94.9 mph in 2015, but it has fallen to 92.8 mph this year, while his wipeout cutter has lost its effectiveness because of his inability to throw it in the strike zone.

Meanwhile, the Phillies are going to have to look for answers in the rotation. They acquired Jason Vargas from the New York Mets prior to the deadline, but Vargas is more of a back-end guy, and his peripherals have been ugly in three starts with Philadelphia.

Philadelphia is still in the hunt for a Wild Card spot, but they need rotational depth as soon as possible.