Against the New York Yankees and an expected sellout crowd at Safeco Field, two long-awaited Mariners debuts take place tonight.

The first is starting pitcher Brandon Morrow, the hard-throwing right-hander who was so good in relief.

The second, third baseman Matt Tuiasosopo, a tools player the team would love to see come on strong in September.

Expect both to undero growing pains.

Morrow hasn't started enough to get consistency, let alone domination. He's on a long learning curve, and September will just be the beginning of that.

As for Tuiasosopo, he may be as good an athlete as there is in the system, a shortstop converted to third because the Mariners thought he'd get to the big leagues sooner.

For those who think there's no reason to watch the Mariners the rest of the way, it's something to consider.

Are these kids the future or more examples of close-but-not-quite stars?