A common term used to describe pain and inflammation manifesting in the heel and arch of the foot, plantar fasciitis (PF) is a disorder of the lower extremity often seen in athletes. One of its most recent victims has been San Diego Padres infielder Jedd Gyorko, who has been battling the condition in his left foot since May 30. Placed on the 15-day disabled list on June 6, more recent news has been encouraging, as he is set to shed the orthotic walking boot he has used to quell the pain, weight bearing load, and foot pronation that can aggravate the injury.
An overuse injury, the causes of PF are varied, evolving from a number of baseball activities that put large amounts of pressure on the heel and connective tissue of the foot arch. Typically, it arises from running, with the excessive loads from bursts of energy and speed seen in sudden starts, stops, and changes in direction often being the culprit. Add to these other twisting and pivoting movements seen while playing defense and prolonged foot pronation—an inward rolling of the foot towards the body's midline—and tiny tears of the plantar fascia create a buildup of scar tissue, resulting in a thickening of the fascia, with deposits of calcified tissue (a separate condition often called a heel spur) also seen in this degenerative process. Individual anatomical differences can also exacerbate the development of PF, with flat feet and cavus deformities—high arches—often cited as risk factors for PF. Positionally, catchers are at particular risk for PF, due to the arrangement of forces on the foot as they sit in their squat being directly focused on the medial aspect of the arch of the foot.
Rarely requiring surgical intervention, the course of action for treating PF is a conservative one, with one eye on the control of pain and inflammatory processes, and the other on working with a player to correct mechanical factors at play in their diagnosis. Anti-inflammatory medications, cortisone injection, and other less common treatments such as iontophoresis, ultrasound, and phonophoresis, all can be used to reduce pain and swelling. Along with the previously mentioned orthotic boot, stretching and mobility exercises involving the fascia as well as the musculature around the foot and calve muscles are also used to modify and improve the mechanical aspects of maintaining health of the foot arch and heel.
For Gyorko and his baseball activities, there are a number of ways that PF has wreaked havoc upon his season. From a base running perspective, the injury is probably at its most painful to Gyorko, but also its least hindering, given his lack of base stealing prowess and speed, in general. Using the broad brushstrokes of base running stats such as Ultimate Base Running, we see a dip in UBR this season compared to last, currently a -0.7, compared to a reasonable 1.4 in 2013. His Speed Score has actually improved this season, currently at a 3.5, up from 2.0 in 2013. Gyorko's ability to take the extra base has dropped this year as well, with a ten percent drop in extras bases taken percentage to 29% in 2014 noted. As alluded to, these big picture snapshots of Gyorko's base running may not provide enough granularity to say whether the PF injury has greatly affected his base running and, to be honest, it's one of the lesser components of his game, and one not necessarily to worry about.
Defensively, the injury to Gyorko becomes a little more dicey. From the perspective of a second baseman—his primary position this season—the double play pivot will be a contentious matter with PF in the left foot. With a push pivot, Gyorko's left foot is against the bag on the outfield side. Once he receives the ball and is ready to transition to throwing, he will push off with the left foot in order to clear himself from the base path. With PF, this transfer and weight shift focusing on the foot injured can be troublesome. With slide and step-over pivots, the left foot is also at risk for further aggravation of the PF and can even be a root cause of the injury, due to the large amounts of weight bearing and pivoting stresses put upon the foot in trying to turn two.
From a fielding perspective, other stresses arising from the sudden starts and stops come into play, with a lot of lateral forces being put upon the injured left foot on plays to Gyorko's right and up the middle. Looking at a small selection of season defensive stats, we do see Gyorko having some issues with the glove. In particular, his DRS as a second baseman has dropped to -4 from -1 in 2013, with a concomitant drop in Revised Zone Rating also seen, currently sitting at .764. Looking at Inside Edge stats, we also see Gyorko suffering a decline this season across the board, with all IE fielding categories showing lower rates of success for the second baseman. At a season level, it appears Gyorko's range and ability to make the plays he did last season are affected, with his PF injury a potential factor in this decline.
The most visible effects of Gyorko's plantar fasciitis is seen in his hitting. Currently at a .215 wOBA and 33 wRC+, the pop that Gyorko displayed last season (23 HR and a 110 wRC+) has all but evaporated this season. While Gyorko only started to complain of foot pain on May 30, with his batting stats and the degenerative nature of PF arising from overuse, it's doubtful that the sentinel event was exactly on this date, prompting many to wonder if the PF has been at the root of Gyorko's hitting woes all season. From a biomechanical aspect, the heel of a hitter's lead foot—for Gyorko, his left—is what truly initiates a swing. Once the lead foot is in place and planted, only then can the abduction and external rotation of the pelvis begin, which allows for rotation around the torso and spine, providing the path for a hitter's hands to come through the zone, during the late acceleration phase. With late acceleration phase also comes extension of the front knee, which can briefly put almost the entire weight of a hitter on his front foot, adding to the pain and inflammation of PF. This all adds up to a number of checkpoints in Gyorko's swing that could be affected by plantar fasciitis, culminating in a slowed bat due to pain causing a more deliberate foot strike with striding to the pitcher, as well as reduced power arising from an avoidance of placing weight on the affected foot, all of this leading to improper and imbalanced swing mechanics borne from a desire to minimize pressure and pain arising from the PF. Other injuries in the hip and knee can also arise from these forced improper mechanics.
Gyorko still has a way to go in terms of a full return from plantar fasciitis, but with adherence to the aggressively conservative treatments, the pain and inflammation should resolve without recurrence. For many, a full return of function comes in several months, which for an athlete such as Gyorko, can be the most excruciating aspect of the injury.
References: Dines, J. S. (2012). Sports medicine of baseball. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins.
Coker, W. L. (2013). Baseball Injuries Case Studies, by Type, in the Major Leagues.. Jefferson: McFarland & Company, Inc., Publishers.