OAKLAND -- Two-sport standout Kyler Murray, who is under contract with the A's, declared for the NFL Draft ahead of Monday's midnight ET deadline, further magnifying a most momentous decision.By opting in to the NFL Draft, a move that is essentially procedural, Murray remains within the confines of his deal

OAKLAND -- Two-sport standout Kyler Murray, who is under contract with the A's, declared for the NFL Draft ahead of Monday's midnight ET deadline, further magnifying a most momentous decision.

By opting in to the NFL Draft, a move that is essentially procedural, Murray remains within the confines of his deal with the A's -- which includes a $4.66 million signing bonus following his first-round selection in last June's MLB Draft -- but he must now decide whether to honor it.

I have declared for the NFL Draft. — Kyler Murray (@TheKylerMurray) January 14, 2019

While time remains for Murray to come to a final decision, ESPN's Adam Schefter reported on Monday that Murray "has informed the Oakland A's of his intention to follow his heart to the NFL, where many project him to be a first-round pick.

"He always can change his mind, but his mind has been made up," Schefter added.

Oklahoma QB Kyler Murray has submitted the paperwork to turn pro and plans to enter the NFL draft. Murray has informed the Oakland A’s of his intention to follow his heart to the NFL, where many project him to be a first-round pick. — Adam Schefter (@AdamSchefter) January 14, 2019

Murray is due in big league camp with the A's by Feb. 15, while the NFL Combine begins on Feb. 26. That means the 21-year-old will likely have to choose one sport -- it's already been determined that he can't play both in the same year -- in the coming weeks, assuming Oakland prevents him from attending the combine.

The A's are doing their part to keep Murray on the diamond. On Sunday, they sent their top executives to meet with Oklahoma's Heisman Trophy-winning quarterback in Dallas in hopes of enticing him to a baseball career with a sweetened deal; sources told MLB.com's Jon Paul Morosi that MLB officials were vetting the A's proposal of a Major League contract for Murray, who is repped by power agent Scott Boras.

Thus far, it's believed that such a deal was not initially discussed as an inducement to help the two sides strike a deal following the Draft -- an arrangement prohibited by MLB. That bodes well for approval of a new deal with the A's, and Murray's entrance into the NFL Draft does not prevent him from agreeing to one.

It's key that any additional money coming to Murray now isn't considered part of his original signing bonus because of the penalties clubs face when exceeding their bonus pool allotments. The A's, who worked with a total bonus pool of $9,553,200 at last year's Draft, selected Murray with the ninth pick overall. That put in place an agreement that would allow Murray to play one more season of college football with Oklahoma. Then historic numbers came for the dynamic quarterback, and a Heisman. Now, he is drawing first-round projections from NFL insiders despite his slight frame.

Should the A's sway the 5-foot-11, 195-pound Murray (he's listed at 5-10 by the Oklahoma football team) to pick baseball over football with a Major League contract that would guarantee him more money, Murray would have four Minor League option years rather than the usual three, because MLB rules grant a fourth option for players expending their third option year before completing five Minor League seasons. Under this scenario, Murray would need to join the A's full-time at the latest by the 2022 season.

On the other hand, if Murray fully commits to the NFL, he would have to return his signing bonus to the A's. However, the club would not receive a compensation pick in this June's MLB Draft, only retaining Murray's professional baseball rights.

Murray, ranked by MLB Pipeline as the A's No. 4 prospect, hit .296/.398/.556 with 10 home runs, 47 RBIs and 10 stolen bases with 189 at-bats as a redshirt sophomore with Oklahoma last spring.

Murray's father, Kevin, faced a similar quandary in 1982. Drafted out of high school in the 18th round by the Brewers, the elder Murray signed with Milwaukee for $35,000. He hit .161 over 41 games in the Appalachian League before deciding to quit baseball and attend Texas A&M to play quarterback.

Jane Lee has covered the A's for MLB.com since 2010.