STANFORD -- If tight end Zach Ertz had hopes of being drafted by the 49ers and staying close to home, he might have been too good for his own good at Stanford's Pro Day on Thursday.

After a disappointing performance at the NFL scouting combine in Indianapolis last month, the former Monte Vista High standout enhanced his standing as a potential first-round draft pick with significantly improved marks in the 40-yard dash and the vertical jump.

Ertz ran 40 times ranging from 4.65 to 4.76 at the combine. But Thursday, he posted times ranging from 4.57 to 4.63 in front of scouts representing all 32 NFL teams on hand to evaluate 12 Stanford draft prospects. Ertz also improved on his combine vertical jump by a whopping five inches -- from 301/2 inches to 351/2.

It remains to be seen how much his stock improves, but he probably re-established his standing as a first-round pick, perhaps one who won't be around when the 49ers select at No. 31.

"I think that's a dream scenario, but my gut tells me after today he won't be there," former 49ers tight end Brent Jones said. "But if he is, they'd better take him."

Jones, who lives in Danville, has been Ertz's tight-ends mentor since Ertz was a high school sophomore. He believes his protégé took a quantum leap with his improved marks.

"He had a great day," Jones said. "He was solid at the combine, but he lit it up today. I think what he did probably put him as the No. 1 tight end in the draft. If you're touching the 4.5s, that puts you at a whole different level."

The 6-foot-6 Ertz was pretty happy, too. He maintained that the marks he posted at the combine weren't an accurate barometer. He conceded he was nervous and out of sorts.

"It was just exhausting, the whole combine setting," Ertz said. "I didn't do as well as I wanted to, so I worked really hard the last month to improve my numbers, and I think I did that today."

"I think I just wasn't feeling it that day," he added, regarding his combine effort. "Luckily, that's why they have Pro Day. If you have something you didn't like at the combine, you can work on it and get better. I just focused on the 40 and the jumps, and that really helped me."

Ertz said being in the Stanford setting with a number of teammates, including fellow tight end Levine Toilolo, helped as well.

"It's good to be out here with all the guys," he said. "The combine is such a microscope, whereas here you're just out here with your best friends competing. It's a lot more relaxing."

Ertz is expected to be the highest draft pick among the Stanford players who took part in Pro Day. Others who were looking to improve their draft stock included tailback Stepfan Taylor, cornerbacks Terrence Brown and Harold Bernard, defensive tackle Terrence Stephens and linebacker Chase Thomas.