DETROIT -- Alex Avila had a glow about him during the recent TigerFest at Comerica Park that made those around him smile, too.
Whether the greater cause of his visible joy was pondering becoming a father for the first time or knowing his knees no longer throbbed like bad toothaches was debatable.
What's not debatable is, Detroits catcher has plenty to smile about with so much to anticipate in 2013.
Last season, the knees, particularly the left one, limited him and contributed to a sizable drop-off in offensive production.
Avila said platelet-rich plasma taken from blood out of his arm and re-injected into his left knee has rejuvenated the stiff and aching joint plagued by tendinitis.
There is a night-and-day difference between the knee this offseason and the last one, Avila said. "The PRP injections worked.
"We talked of doing it since the middle of last season, but you need to take five to seven days off after the injections. I did not want to take that kind ...