Soft Tissue Repair
When talking nutrition/supplements for sports injury repair (specifically soft tissue injury), it's important to understand what's happening during the injury repair process. For starters, although we may perceive injury as chaotic with the pain, swelling, dysfunction, etc, when we look at things biologically we see that injury does lead to an organized, consistent pattern of repair. Researchers and clinicians typically break this pattern down into 3 defined stages.

Stage 1: Inflammation (lasts up to ~4 days post-injury) Regardless of the injury, muscle, bone, and vascular damage likely occurs. As a result, the injured tissues are deprived of their normal flow of oxygen and nutrient-rich blood. This reduction in blood flow, as well as the actual physical damage suffered, leads to cell death.
In an attempt to clear out the damaged/dead cells and help lay down new cells, the body initiates the inflammatory process.
Inflammation itself is stimulated by the increased movement of inflammatory/immune chemicals (leukocytes, neutrophils, macrophages, phagocytes, etc) into the injured areas. These chemicals take care of the cellular debris as well as attract plasma (fluid from the blood) and blood proteins to the site of injury. The result of this biochemical process - injured tissues are removed and the process of repair is initiated.
Throughout the inflammatory process, the following can be expected:
A) Pain - believed to be a function of two things. First, certain chemicals involved in injury repair (substance P, calcitonin, histamines, cytokines) may interact with local pain receptors to cause the pain associated with inflammation. Further, as inflammation proceeds, pain may also result from the swelling/pressure placed on the nerve endings.
B) Swelling - a result of fluid seeping through damaged and now hyper permeable vessels into the damaged tissues. These vessels can be damaged by the initial trauma. Further, they can be altered chemically during the inflammatory process.
C) Redness and Heat - additional blood is shunted to the area of injury, resulting in increased heat. This is due to vasodilation up-stream of the injury and constriction downstream. The upstream vasodilation is thought to be related to nitric oxide activity.
Now here's an important note. Although painful and irritating, the inflammatory process is necessary for repair. Without inflammation, injuries would not heal. So any attempt at eliminating inflammation is a mistake, especially in acute injury.
Chronic injury is altogether different. Excessive inflammation, especially if it’s prolonged, can lead to other problems including excessive macrophage activity at the site of inflammation and continued tissue destruction. This is why inflammation management is an important concept in injury recovery and why anti-inflammatory agents are often prescribed by physicians during chronic pain.

Step 2: The Proliferative Phase (from ~4 days to ~21 days) Once the inflammation begins to subside, most of the damaged tissues will have been removed from the site of injury and new vasculature will have developed. This restoration of oxygen and nutrient flow to the damaged area allows for fibroblast proliferation/multiplication. Once this occurs, collagen and fibronectin are laid down; forming what is commonly called "scar tissue."
Importantly, scar tissue will lay down in alignment with the forces being placed on the area. Further, this scar tissue will contract/shorten as it matures (due to fibroblast differentiation into myoblasts, which are similar to smooth muscle cells) to reduce the size of the injury.

Step 3: Remodeling Phase of Injury (from ~21 days to ~2 yrs) Eventually, the scar tissue formed above (typically made up of type II collagen) will be degraded and type I collagen (much stronger) will be laid down in its place. Although this new tissue will never likely be 100% normal, it can become ~80% as strong as uninjured tissue.
Further, as this tissue is aligned along tension lines, it's important to recovery that the tissue be used in normal functional activity throughout the recovery process. This will help maintain the length of the scar tissue as well as help arrange the tissue in an organized pattern in line with adjacent soft tissue fibers.
Hopefully this helps describe the injury repair process. In the end, this predictable pattern of soft tissue healing can give us clues as to how injuries can be managed using physical therapy, manual therapy, nutritional strategies, and drug interventions.