Fernando Tatis Jr. and the San Diego Padres are working on a contract extension that could reach 10 years and more than $300 million, according to MLB Network's Jon Heyman. 

The 22-year-old is eligible for arbitration for the next three seasons and isn't scheduled to become an unrestricted free agent until 2025. 

Any deal within the range of the $300-plus million report would make Tatis Jr. the highest-paid active shortstop and at least border on the largest deal for a shortstop in MLB history. 

The Texas Rangers' Elvis Andrus' carries an eight-year, $120 million deal, which is tied for the lead at the position. The Boston Red Sox gave Xander Bogaerts $120 million as well over six years. Alex Rodriguez holds the record for the largest shortstop pact at 10 years, $275 million, signed at age 32. That contract with the New York Yankees broke Rodriguez's own record of 10 years, $252 million he signed with the Texas Rangers in 2000. 

Only six active MLB players have a contract worth $300 million or more—Mike Trout, Mookie Betts, Bryce Harper, Giancarlo Stanton, Gerrit Cole and Manny Machado—with Trout leading the league in contract value with a 12-year, $426.5 million deal. 

There's little question whether Tatis is worth that type of money.

Already one of the most electric players in the majors, Tatis slashed .277/.366/.571 with 17 home runs and 45 RBI in 59 games last year. It was just his second season in the majors, and he earned a Silver Slugger and finished fourth in NL MVP voting. 

As the Padres' championship window opens wide, the club is reportedly working to make sure one of the best players in baseball remains in San Diego for at least another decade.