Shohei Ohtani is the Angels’ starting pitcher Sunday. Why?

The Angels are playing for 2019. So why are they so determined for Shohei Ohtani to pitch in 2018?

Ohtani is scheduled to start Sunday for the Angels, in what would be his first pitching appearance in three months. On the day after his last start, doctors detected a torn ligament in his pitching elbow.

That hasn’t kept baseball’s most interesting player off the field. Ohtani hit his 15th home run of the season Monday, in the process becoming the third player in major league history — and the first since Babe Ruth in 1919 — to hit 15 home runs and win four games in the same season.

In June, Ohtani had injections of platelet-rich plasma and stem cells, in the hope the injury might heal without surgery. He has been throwing for several weeks.

By Ohtani coming back this season, even with the Angels out of the pennant race, the team can assess whether he can pitch comfortably and effectively.

If not, he can undergo elbow-ligament replacement surgery now, and he could return to pitching for the start of the 2020 season. If the Angels waited until next season to assess Ohtani, and if he then needed surgery, he probably would not be able to return to pitching until late in the 2020 season.

There are no guarantees. The Angels’ Garrett Richards returned from similar therapy, pitched 16 games, and then needed the surgery anyway.

Ohtani’s availability for the 2019 season also affects how the Angels might be able to use Albert Pujols.

If Ohtani is pitching and hitting, and if the Angels use him as they did this season, he would not be in the starting lineup on the day before he pitches, the day he pitches and the day after he pitches. That would leave plenty of at-bats for Pujols at designated hitter.

If Ohtani can hit but not pitch, Pujols might have to play extensively at first base to stay in the starting lineup, at least against right-handers. It is too soon to know whether his body would be able to handle that workload, or even if doctors would recommend it.

Pujols, 38, underwent season-ending knee surgery Wednesday, the fourth time in seven years he has undergone surgery on a knee or foot. He played 70 games at first base this season, up from 28 last season.

bill.shaikin@latimes.com

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