Coach Weston had HGH (Human Growth Hormone or anabolic steroids) planted on him, but he wouldn't have gotten arrested. At worst it would disqualify the team from competing. Russian authorities threaten with lifetime prison sentence, but steroids are legal in Russia.
It was said that the penalty for espionage in Russia is death. Russia has suspended usage of capital punishment and it has not been used since 1996; however, it does exist on the books for five possible crimes (all involving murder or attempted murder), none of which include espionage.
The plot includes the U.S. track and field team going to Moscow to compete in an international event. Assuming these events are taking place in 2016, this would be impossible, as the International Association of Athletics Federations (IAAF) suspended the All-Russia Athletic Federation in November 2015 and Russia is unable to host any international track and field competitions for the foreseeable future.
Since Coach Heston was in fact a Russian double agent it made no sense whatsoever for the Russians to arrest him in Moscow and to expose his cover.
When MacLeish brings his documents into FBI Deputy Director Ritter, he mentions 7 years of documents. But when Ritter is discussing the documents with Hannah Wells, he says 10 years.
Secretary of State Paulsen (Maria Ricossa) suggests Russia planted drugs on a visiting American track coach "as a pretense for the arrest." Unless she was suggesting the arrest did not occur, then the drugs would be pretext - not pretense - making it a pretextual arrest.