The baseball world is buzzing about Japanese star pitcher and hitter Shohei Ohtani, who has agreed to play with the Angels. (0:57)

Even before Shohei Ohtani decided on the Los Angeles Angels on Friday afternoon, a number of MLB officials told ESPN that they wouldn't be surprised if his decision, regardless of the team, spawned an immediate investigation into how the process played out.

Commissioner Rob Manfred and other MLB officials have been giving the Ohtani case extraordinary scrutiny, with repeated warnings of bans and penalties for anyone found in violation.

Prior to Otani's agreement with the Angels on Friday afternoon, various team officials said they expect a layers-deep review into how the decision was made.

MLB, after finalizing its agreement with the Nippon Baseball League on Dec. 1 that allowed bidding to begin, issued a memo to all teams and baseball executives that contained paragraphs again warning against any form of cheating.

Teams were told, again, that they could attempt to persuade the two-way pitching and hitting star from Japan to join their team based on the merits of their respective organizations and their cities, but they were warned against discussing future contracts and business relationships, and against third-party machinations -- paying off someone who might have influence with Ohtani, for example, or making quid-pro-quo promises outside of the rules.

"The commissioner's attention on this has been unprecedented," a team executive told ESPN. "There's a lot of avenues for cheating, and I think [MLB is] well-aware of that."

Commissioner Rob Manfred and other MLB officials have repeatedly warned teams about the rules involved in the pursuit of Japanese star Shohei Ohtani. AP Photo/Koji Sasahara, File

Baseball has seen two high-profile violations of its international signing rules in recent years since MLB and the players' association negotiated spending limits on international signings in the collective bargaining agreement that went into effect in 2012, leveling the playing field for small- and mid-market teams.

The Boston Red Sox were deemed to have violated rules and were stripped of some prospects they had signed in addition to a one-year ban on signing international amateur players. Last month, after MLB had received a flood of tips and complaints from other teams, the Atlanta Braves received the most significant penalties ever levied for rule-breaking with international signings, and Braves general manager John Coppolella joined Pete Rose and others on the short list of those given a lifetime ban.

Manfred has worked to regulate the Wild West nature of international signings, an arena in which off-the-book payoffs and cheating were standard operating procedure for decades. In the years since, MLB began exerting much greater effort in enforcing its own rules.

Said another club official to ESPN: "I think the perspective of the commissioner's office has been, 'Hey, we set up this system to limit your [financial] exposure, so you need to play by the rules.'"

Prior to his decision, as Ohtani moved closer to jumping from the Nippon-Ham Fighters in Japan to an MLB club, Manfred and Dan Halem, the commissioner's chief legal officer, warned club executives time and again about following the rules in their pursuit of the 23-year-old star.

"I can't recall a topic more fully communicated with teams than the rules of engagement with Ohtani," another official told ESPN.

Manfred and Halem have spoken repeatedly at owners meetings about the potential for rule-breaking. At the most recent general manager meetings, last month in Orlando, Florida, Halem reiterated to club officials that any team found guilty of violating the rules would be hit hard.