The phrase "are suspected to play" is correct and usable in written English.
It can be used when discussing theories or beliefs about someone's involvement or role in a particular situation or event.
Example: "The researchers believe that certain environmental factors are suspected to play a significant role in the development of the disease."
Alternatives: "are thought to contribute" or "are believed to influence".
The accumulation of mtDNA mutations throughout an organism's life span are suspected to play an important role in aging, as well as in the development of certain cancers and other diseases.
Autoantibodies known as anti-Ro and anti-La, which are found in patients with Sjögren syndrome and in patients with systemic lupus, are suspected to play a role in photosensitivity, characterized by the development of skin rashes in response to exposure to ultraviolet light.
Tensile forces present on the leading edge of the inserts due to the sliding contact with rock are suspected to play a significant role.
While changes in local blood flow are suspected to play a role therein, hemodynamics in arteries with overlapping stents remain poorly understood.
Combined with the analysis of burial history and fluid inclusions, the stress fields during three periods (the Yanshanian period, Himalayan period and neotectonic period) are suspected to play a critical role in fracture sealing.
Combing genome databases for similar sequences, they and others have subsequently identified 11 human aquaporins--some of which are suspected to play a role in diseases--and many more in bacteria and plants.
Little is known about the perception of chemical marker compounds, although the vomeronasal organ (Jacobson organ) is suspected to play an important role.
In people with Down syndrome, the slower pace of neuron growth in the hippocampus is suspected to play a key role in cognitive deficits.
Thus, the bacterial composition of the oral cavity is suspected to play an important role in the development of caries and gum disease.
After about four years of this contract, with my colleague Junming Le, we'd made an antibody to the cytokine TNF, which was suspected to play a role in sepsis and some autoimmune conditions.
The DNMTs have long been suspected to play a role in oncogenesis, as well.
